Automatic Room LampDESCRIPTION :First, let us understand why to use Automatic room Lamp? Now-a-days we are going through lots of advertisments of saving electric energy. With the help of Automatic room Lamp we can save and reuse energy. Find the simple block diagram of Automatic room Lamp.

BLOCK DIAGRAM of LampThe above block diagram of Automatic room Lamp used to disables the room lamp at day time and enables at night night time. Light Dependant resister(LDR) is the key element of Automatic room Lamp.Operation:We need to fix LDR Circuit near to the window/door of home where it can receive maximum sunlight.At day time if we open the door, the resistance of LDR Circuit reduces and leads the transister to remain in cut-off state. So the relay doesnot energize enough,and lamp remains off.At night time, the resistance of LDR Circuit becomes high and its makes the transistor from cut off state to conducting state. The relay becomes energize and makes lamp to switch on.

We need power supply too operate the following operation.

BLOCK DIAGRAM OF Power SupplyThis is block diagram of basic power supply circuit. Transformer is used to step up or step down the input voltage. The bridge circuit is used to convert the alernating current to a pulsating direct current. Since pulsating dc is not desirable, we used filter to convert it to more desirable dc. Regulator is used to maaintain the output of the power supply at a constant level.Benefits :Operated only at +5V(d.c)No use of man powerUsed in: Houses Educational Institutions Medical halls Shopping Malls

Metal Detector CircuitSeptember 12, 2013 By Administrator 3 Comments Introduction:Metal detector is very common devices for checking the person in shopping malls, hotels, cinema halls to ensure that person is not carrying any explosive metals or illegal things like guns, bombs etc. metal detectors can be created easily and the circuit is not that complex.Block Diagram of Metal Detector:

The LC circuit is nothing but inductor and capacitor which is connecter in parallel. The LC circuit will trigger the proximity sensor if it detects any metal near to it. Proximity sensor will give glow the led, and also make the buzz with the help of the buzzer.Main Components in Metal Detector Circuit:LC CIRCUIT: LC Circuit is a resonating circuit which will resonate when exact same frequency material comes near. The LC circuit consist of inductor and capacitor connected in parallel , when the capacitor is fully charged the charge of the capacitor will be given to the inductor, here inductor will have improve its magnetic field. After some time the capacitor will have no charge and current from the inductor will be given to the capacitor in a reverse polarity and capacitor will get charge and now the inductor magnetic field and current will become nil. Again charged capacitor will give current to the inductor to improve its magnetic field. Note inductor is a magnetic field storage device and capacitor is electric field storage device.PROXIMTY SENSOR: The proximity sensor can detect the objects with out any physical interference. The proximity sensor will work same as infrared sensor, proximity also release a signal, it will not give output unless and until there is no change in the reflected back signal, If there is a change in signal it will detect and give the output accordingly. There are different proximity sensors for example to detect plastic material we can use capacitive type proximity and for metals we should use inductive type.Circuit Diagram of Metal Detector:

Metal Detector Circuit Explanation: When the LC circuit that is L1 and C1 has got any resonating frequency from any metal which is near to it, electric field will be created which will lead to induces current in the coil and changes in the signal flow through the coil. Variable resistor is used to change the proximity sensor value equal to the LC circuit, it is better to check the value when there is coil not near to the metal. When the metal is detected the LC circuit will have changed signal. The changed signal is given to the proximity detector (TDA 0161), which will detect the change in the signal and react accordingly. The output of the proximity sensor will be of 1mA when there is no metal detected and it will be around 10mA when coil is near to the metal When the output pin is high the resistor R3 will provide positive voltage to transistor Q1. Q1 will be turned on and led will glow and buzzer will give the buzz. Resistor r2 is used to limit the current flow.Curtain Opener and Closer CircuitDecember 3, 2013 By Administrator Leave a Comment This circuit will open and close the curtain of your home and office just by pushing a switch. So with the help of this unique circuit, we do not need to move from one place to open and close the curtain. This circuit is used for household use, particularly for smaller doors and windows. Due to its small size and readily available components, it can be effortlessly fixed with a curtain. You can also provide power supply to the circuit with the help of adapter existing in the market.Curtain Opener and Closer Circuit Diagram:

Circuit Diagram of Curtain Opener and Closer ElectronicsHub.OrgComponents used in this Circuit: IC IC1 (CD4013) IC2 (ULN2003) Resistor R1-R4 (5.6k) R6, R5 (1K) C1 (. 1uf) Stepper MotorDescription:This circuit is made up of two ICs named CD4013 and ULN2003 with few more easily available components.CD4013 IC contains two self-governing D type flip flop on a single chip which exists in one of two states that is 0 or 1 and can store information. Each module is further capable of group of pin outs assigned as data, set, reset, clock input and a couple complementary output Q and .How D Type Flip Flop Works:D type flip flop has one input referred to as D input or data input. The truth table of D type flip flop is shown below:This is equivalent to saying that input data appear at the output, at the end of the clock pulse. Thus the transfer of data from input to output is delayed and hence delay (D) flip flop. Thats why it is used as a delay device or latch to store 1 bit binary information. In this clock (CK) input line controls the flip flop which is used to determine whether the input data is recognized or ignored. The input is normally a clock signal. If the clock input is binary high means logic 1 the data on the D line is stored in the flip flop. As long as clock line is high the normal output will simply follow or track the D input. If the CK line is low or it is binary 0 the D input line is recognized. Means the bit store in the flip flop previously retained. The D line can do anything. It will ignore if CK is low.CD 4013 comes in 14 pin dual inline package. Before understanding the working of circuit diagram first have a look at its pin layout.

CD 4013 Pin Diagram Electronics Hub1. Pins 1, 2, 13 and 12 are known as complimentary outputs hence both are presented as output but with inverse of each other. Like for first flip flop Q is 1 then will be 0. The same is also there for another set of flip flop.2. Pin 5 and 9 are known as Data pins they are normally connected to one of the outputs can be Q or enlargingnction of enlargement the appsquare wavesclock for square wave and for other waves they may be ended to any other logic level means they may be either connected to supply line or to the ground of the circuit. In our circuit we have attached and Data pin 5 as one.3. Pin 3 and 11 are known as Clock input. It is used to receive the input signal for working of D type flip flop. You can provide signals with the help of transistor configured as astable multivibrator or you can provide signals through logic gate like by NANA gate or NOR gate. In our circuit we are providing the clock input with the help transistor.4. Pin 4, 6 and 10, 8 are known as set and reset pin whenever any one of the pin goes high we will receive the output. For protection these pins are assigned to a logic level normally they are grounded with a high value resistor. Once this is completed the input can be made to alternately react to positive peak pulses to control the logic stage of the Q and output alternately.5. Pin 14 and 7 are called supply and ground pin respectively. Pin 14 receives the power supply input that is Vcc which should not be more 15V otherwise it will tear down the IC and pin 7 is ground and it should be connected to the negative supply input of IC.And ULN2003 is basically a Darlington array of high voltage as well as of high current every ULN2003 IC comprise seven unlock collector Darlington couples along with common emitter. ULN2003 is furthermore commonly used in a large variety of loads with the assist of relay drivers or may be employed to drive a stepper motor. ULN2003 works with 5V TTL and CMOS logic devices. Each channel or else Darlington couple in ULN2003 is marked at 500mA and be able to resist peak current of 600mA.Below pin diagram of IC ULN2003 is shown:

ULN2003 Pin DiagramWorking on this circuit is very easy to understand. Assemble the circuit properly and cross check the connection. In this circuit we are utilizing both the flip.If you want to open the curtain just press switch S1 for some time. This will supply the voltage to pin 6 of IC1 (which is set pin) as one end of the switch is connected with power supply and when pin 6 goes high it will provide you the highest output at pin 1 of IC1 that is at Q output. Which in turn makes the pin 2 of IC2 also high and the geared motor connected at the output start revolving in the close wise direction to open the curtain. Now when the curtain is open properly or you want to stop the motor in between just press the switch S2 connected at pin 4 of IC1 which is reset pin and this is used to off or stop the stepper motor when the curtain in fully open or you want to stop in between.A similar occurrence will happen if you want to close the curtain. Just press switch S3 for some time connected to pin 8 of IC1 which is also a set pin. Geared motor starts running in anticlockwise direction. Now when the curtain is close or you want to stop in between press the switch S4 to off the stepper motor. Therefore you can now open and close your curtain just by sitting in one place, without moving just by pressing the switch.Fire Alarm with Siren SoundJune 8, 2013 By Administrator 2 Comments Fire Alarm Circuit:This circuit alerts us when there is a fire accident at home by ringing a siren sound. You might have seen fire alarms earlier but this is quite different as it generates a siren sound instead of a buzzer and also it uses basic components to generate that siren sound.We are aware that there are many integrated circuits which can be used to generate the siren effect but we preferred to use basic electronics components like resistors, capacitors and transistors to generate it so that you will clearly understand the internal working of it and it will be much useful for you as you will gain more knowledge by analyzing it instead of simply going or pre designed integrated circuits.Fire Alarm Circuit Diagram:Description:This circuit uses a thermistor to sense the temperature. When it senses that the temperature of the environment is increasing above a given threshold, then it gives a signal. The temperature at which the circuit detects fire can be adjusted by using the potentiometer arrangement at RV2.Get an idea about Thermistor Temperature Sensing Alarm if you are interested.When the temperature increases above the set value, the potentiometer arrangement produces a high voltage. This voltage is then given to BC547 transistor in common emitter mode. It is an NPN general purpose transistor. When the base is given a high input, it gets turned on. When the transistor is turned on, its collector voltage is reduced to low as the collector to emitter voltage decreases. The collector output voltage of the first transistor is given to the base as an input to the second BC 547 NPN transistor. This transistor too is in common emitter mode and as the input is low when the temperature threshold is reached, the output at the collector will rise high. In this state, it will turn on the next transistor, i.e BC107. This transistor will now act as a switch for the siren circuit. This transistor can bear power quite larger than the BC547 and it is also equipped with a heat sink for that purpose.When the BC107 transistor turns on, it allows current to pass from power supply to ground through collector thereby acting as an electronically controlled switch. When the current is passing, the siren circuit which is assembled as the load to the circuit is turned ON. Then you can hear the siren sound through the buzzer. The capacitors used in the circuit are the main components in producing the siren effect. The principle involved in generating the siren effect is to make an oscillator with an envelope which periodically increases and decreases so as to generate that effect.Remote Operated Alarm CircuitJune 7, 2013 By Administrator 3 Comments This circuit rings an alarm when you point a TV remote at it and press on any button. This can be used as a calling bell to call your assistant. This circuit can have more applications than those mentioned here. You can use it for many other applications depending on your creativity and necessity.Remote Controlled Alarm Circuit Diagram:Description:TSOP 1738 infrared photo sensing module is used to sense the IR rays with about 38KHz of frequency. This module helps us to reduce interference from other natural IR signals from the environment. This does not take continuous IR rays. IT filters out all other IR rays and takes only the IR rays with 38 KHz as an input. This avoids interference from sun rays, hot objects emitting IR rays, etc. Pin-1 of TSOP 1738 is given to ground, pin-2 is given the input signal and pin 3 is where we get the output from.The output from the TSOP sensor is given to the general purpose PNP transistor BC557. The output of the transistor is given to the input of IC 555 timer. The IC 555 timer is arranged in the monostable mode. In this mode, the circuit stays in ON mode for a short time after it receives the input triggering. The 555 ic in the monostable mode gets triggered by the preceding circuit when the TSOP sensor receives a valid IR signal. By valid IR signal, we mean the IR signal with 38KHz frequency. The TSOP filters all other frequencies and thereby reducing interference to a great extent as described earlier.Most television remotes are equipped with IR transmitters which emit IR rays at a frequency of 38 KHz. So, by using such TV remotes, we can trigger the circuit. When the circuit is triggered, it turns ON the buzzer which is at the output.The TSOP sensor should be powered by a voltage of 5V for proper operation. That is why we are using a zener diode of 5.1 volt. The zener diode is connected in reverse bias. In this mode, it is used as a voltage regulator. In this mode, the zener diode maintains the voltage at 5.1V even if there is any change in the current passing through it. Although it may not be an ideal voltage regulator, it is one of the simplest, cost effective and easy to use voltage regulators due to which we have chosen it for using in out circuit.The capacitor which is used at pin 5 of the IC 555 is an optional component. It actually is used in general to avoid noise but in this case, we do not think it has much prominence. It is not wrong to use it here but it is not mandatory too. However, if you have a spare capacitor of that value, you can use it.This circuit is powered using a 9V power supply. You can either use a direct current battery power supply using a PP3 battery or else, you may use a DC adapter with 9V output for this purpose depending on your availability.Electronics Hub HOME PROJECT IDEAS B.TECH ANDROID FREE PROJECT CIRCUITS ELECTRONICS TUTORIALS MINI PROJECTS CALCULATORS CONTACT US Home Security Alarm Circuit Security Alarm CircuitDecember 9, 2013 By Administrator 5 Comments This circuit will help you to guard your precious documents as well as jewellery from intruders or theft. All you need is just to place this circuit in front of the locker or below the mat so when any unknown person come and walk over the switch, the circuit will trigger and sound of alarm comes. The main benefit of the circuit is that these can be implied in two places at a time as two different switches produces two different sounds.Related Post: Panic Alarm CircuitCircuit Diagram of Security Alarm:

Security Alarm Circuit Diagram ElectronicsHub.OrgCircuit Components: Resistor R1, R2 (100K) 2 R3 (1.2K) 1 R4 (47E) 1 T1 (BC547) 1 T2 (BC558) 1 D1, D2 (1N4007) 2 C1 (. 1uf) 1 S1, S2 2 Speaker 11. Resistor: Resistors are the passive device with two terminals. They are mainly used in the circuit to restrict the flow of current across any of the circuits. The current flow from the resistor is directly proportional to the voltage that is given across the terminals of the resistor. In the market resistors are mainly available in two broad categories: 1. Fixed resistor- It actually means that the resistor whose value cannot be change and remain what its mark on it.2. Variable Resistor- It means that the value of resistance can vary within the range marked over it. For e.g. If the value of 5k is marked on it then it implies that the value of the resistor can vary from 0-5k. The value of the resistor can be calculated either with the help of multimeter or with the help of color code over the resistor.2. Diodes - It is a device with two terminals and have a asymmetric attribute which means that it permit the flow of current in one of the directions while the flow of high resistance is from another direction. Hence in it flow of current is in one way only and block the other way for the current flow. The two terminals in diode named as anode and cathode. AC current can be converted into DC with the help of diode unidirectional behaviour.3. Transistor - transistor is a three terminal electronic device used to amplify weak input signals. A transistor consist of two PN junction diode connected back to back. Transistor are of different type such as bipolar junction transistor, Field effect transistor and photo transistor. They are mostly used in electrical appliances due their smaller size and light weight. In addition they posses less power hence have greater efficiency.4. Speaker- it is a transducer which creates sound in reaction of the electrical auditory signal given in the input.5. Capacitor- Electric charges are being stored by these two terminal components which is passive by nature. A dielectric medium is used which is used to separate two conductors. It started at the time when the potential variation occurs in the conductors polarizes the dipole ions to hold the charge in the medium which is dielectric. There are two varieties of capacitor available in the market - 1. Polarized capacitor- Capacitor marked with and + sign. They are mainly used to hold the charge. And before troubleshooting these capacitors carefully discharge them as they hold charges there is a risk of shock.2. Non polarized capacitor Capacitors which do not have any polarity marked over it. They are mainly used to remove the noises appeared while converting AC into DC.Important Post: Pull Pin Security Alarm CircuitWorking of Security Alarm Circuit:S1 and S2 are the two switches that are used in the circuit so that both can be put in two different places i.e. one of them can put in front of the locker while another one can be placed on the front door. When the switch S1 is pressed diode D1 which is linked with it starts conducting as the transistor T1 and T2, which is attached with the resistor begin its conduction. For the oscillation purpose Transistor T1 and T2 gets a positive feedback which is provided by capacitor C1. The presence of any intruder is indicated by the low tone frequency which is generated when switch S1 is pressed.Same kind of condition occurs when switch S2 is pressed. Diode D2 which is linked with the switch S2 begin its conduction and offers power supply the transistor T1 and T2, which is in the waking state and as a result sound comes from the speaker attached to it. But in this instance a high frequency tone comes out which is a sign that there is some intruder present around the locker. The sound that came from the speaker can only be stopped by cut off the power supply.Related Posts Dummy Alarm Circuit Pull Pin Security Alarm System Water Level Alarm Using 555 Timer UP/DOWN Fading LED LightsComments1. sonu says: December 11, 2013 at 4:22 am Hi,Nice circuitReply 2. RK Murthy Challa says: December 13, 2013 at 7:54 am I have just seen UR Circuit. Any how it seems to be good and useful for domestic use and I will try soon. ThanQ for publishing such useful circuits.Reply 3. sumithra says: December 20, 2013 at 9:58 am hi it is a nice circuit and very useful for domestic purpose.it give a safety as well high sequirity for expensive things.thank u for publishingReply 4. bharathi says: February 27, 2014 at 11:33 am hi its a very nice circuitReply 5. SARAVANAN says: June 16, 2014 at 6:38 am its very nice projects dont miss it .Reply Speak Your Mind Top of FormName *Email *Website

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Delivered by FeedBurnerBottom of Form Return to top of pageCopyright 2014 Electronicshub.orgSimple Fire Alarm Circuits at Low CostOctober 7, 2013 By Administrator 6 Comments Introduction to Fire Alarms:Just imagine when an apartment is caught fire in the second floor! The people in the second floor can easily recognize the fire and can inform to their neighbors and run for their lives; but people in the first, third and fourth floors may not know the fire accident and busy with their work. This will be great danger to the people live and property also. So there should be an alarm to inform to all people in the apartment in which the fire has taken place and act immediately. Here fire alarm plays a key and important role. It will detect the fire automatically and inform to the people with an alarm. Now-a-days, fire alarms are must for the apartments, theaters, hotels, restaurants, coal mines, petrol bunks or gas stations, etc.Here are two simple fire alarm circuits which will use different concepts and different components for generating the fire alarm. The main basic concept is almost same that sensing the fire or heat by the component and giving that information to the remaining circuit to give alarm.Fire Alarm Circuit Using Germanium Diode:This is a simple fire alarm circuit using Germanium Diode and 555 timer. In this circuit Germanium Diode play very important role in detecting the fire. This circuit is very easy to construct, cost effective and implementable.Block Diagram of Fire Alarm Circuit Using Germanium Diode:Here is the simple fire alarm circuit which costs less than 100 rupees. The key component in the circuit is DR25 (germanium diode) whose resistance will decrease with increase in temperature. The conduction of germanium diode will start at 70 degrees. So we may use germanium diode as a heat sensor. When the temperature is more than 70 degree, the germanium diode will conduct and trigger the NE555 timer through a transistor. The NE555 is configured in astable multivibrator and make the buzzer to alarm when germanium diode conducts. So that we can get alert and act according to the alarm.Circuit Diagram of Fire Alarm Using Germanium Diode:

Circuit Explanation: The DR25 germanium diode is heat sensor which will conduct when temperature is increased at certain point. The DR25 is made reverse biased in the circuit. It will conduct only when it is more than 70degree of room temperature. The DR25 is connected to the transistor in reverse bias, which has high reverse resistance (more than 10K ohm) and does not make the transistor to turn off which is connected to the reset pin of 555 timer. The reset pin of 555timer will be in ground level when the transistor is turned off. Here, the 555 timer is configured as astable multivibrator. When more than 70degrees in room temperature occurred, the resistance of DR25 diode drops to 1k ohm which will make the transistor to turn off and make the reset pin to go high. This will generate the output at pin3 and make the sound through the alarm. We can use 3 or more diodes in reverse bias connected in parallel and placed in different room. If there is fire accident, it will sense and make the alarm.Note:1. If DR25 germanium diode is available, you can still use AC128, AC188 or 2N360 germanium transistors. Use base and emitter junctions in place of cathode and anode.2. Diode must be connected to the circuit in reverse bias.Fire Alarm Circuit Using LM341:Here is another small project on fire alarm. When a fire accident is happened in home or office, it will detect the fire (intensity of fire in the room) at instant and give the alarm so we can be ready and act accordingly.Block Diagram of Fire Alarm Circuit Using LM341:

The thermistor is the main component which detects the fire by sudden change in the room temperature because of the heat generated by the fire. The thermistor will detect the heat and give the information to the LM741 OP-AMP. The op-amp will make the NE555 to generate pulse which has been given to a buzzer to buzz.Main components:Thermistor: The resistance of the thermistor will change according to the temperature. There are two types of thermistors of which one type of thermistor will increase its resistance with increase in temperature called as positive temperature coefficient and the other type of thermistor will decrease its resistance with increase in temperature called as negative temperature coefficient. In this project, we use the thermistor which will have lower resistance with respect to the temperature (negative temperature coefficient thermistor). Thermistor has large applications in consumer electronics, food preservation sectors etc.LM741: LM741 is an operational amplifier which will work according to the difference in the input voltages. LM741 has following features like high current driving, voltage gain, noise amplification and also provide low output impedance. LM741 can also used as a short circuit protection.Circuit Diagram of Fire Alarm Using LM741:

Circuit Explanation: There are two modes in this project: Mode 1: How the circuit will work if there is no fire Mode 2: How the circuit will work if there is fire.Let us now study about these 2 modes in detailed way. Mode 1 When there is no fire: The thermistor will have high resistance and there will be no difference in the voltages coming to the LM741 at pin2 and pin3 so there will be no output which will help to trigger the timer. Mode 2 When Fire started: The thermistor resistance will go down to the heat produced by the fire and the resistor R3. And thermistor will act as a potential divider circuit resulting a low voltage at pin2 of LM741 as the temperature goes high. The reference voltage is given by the R4 to the pin3 when there is a difference in the voltage. The pin6 will trigger the timer configured as astable multivibrator. NE555 timer will activate the speaker which makes the alarm. The variable resistor R5 will vary according to the difference in the voltage of the op amp. According to the resistor R5, the timer will generate pulse. If temperature goes high, the speaker will make high noise.Fire Alarm Applications: Fire alarms can be used in any place like parks, theaters, hotels, restaurants, boats, ships, etc. Fire alarms can be also used as temperature sensors in some applications, when the temperature goes up abruptly it can inform. Fire alarm can be used in our home for safety purpose and it is a very good precautionary measure.Related PostsUSB LED Lamp CircuitJuly 14, 2014 By Administrator Leave a Comment Universal Serial Bus is acronym for USB. USB was a standard developed to simplify the connections between computer and its peripheral. Due to the low light on the CPU, one cannot see inside it at the time of power loss and it is difficult to see the keyboard. It is required to be moved from its original place to the light to do all these. So a lamp that is powered using USB can solve this problem. As the USB port produces 5v at the output, it can be used to light up the simple lamp circuit. Thus there is no need of moving the CPU from one place to another and again connecting all the wires.USB LED Lamp Circuit Diagram:

USB LED Lights Circuit DiagramCircuit Components: USB Light Emitting Diodes D1, D2, D3, D4. Resistors R1, R2, R3, R4.USB LED Lamp Circuit Design:The circuit mainly consists of USB. USBs can be divided into mainly of two standard types USB of A type and USB of B type. These different types of USBs connectors differ in their shapes .Type A USB can be used with the upstream devices such as USB hub or host .Type B USB can be used with downstream devices such as printers .These cables will have same number of pins but they differ mechanically. Many versions in USB were released. The first version USB 1.0 and 1.1 had the data rate of 12 Mbps.USB 2.0 has data rate of 480 Mbps.USB 3.0 is expected to have data rate of 4.8 Gbps.Do you have any idea about the circuit 3X3X3 LED Cube CircuitUSB used here is of type A. It has 4 pins. These pins are VCC, GND, D+, D- pins are the data pins. VCC pin outputs the voltage of 5V. The USB used here is of type A. This can be simply connected to the USB port of the computer.LED is a semiconductor device with two leads. Generally LEDs are used for indicating. It is similar to a normal P-N junction diode. The energy emitted is in the form of light when applied with the required voltage, while normal P-N junction diode emits energy in the form of heat. The color of light emitted depends on the band gap of the semiconductor. The LEDs used here are normal LEDs. They have voltage drop of 3.6V. The current required by the LEDs is 40mA. Initially these LEDs are limited to the red color, later high power LEDs such as blue LEDs, white LEDs were developed.A resistor of 100kohms is connected between the Light Emitting Diode and the USB. This acts as a current limiting resistor. As the LEDs require maximum current of 40mA to glow with full brightness, they are required to protect from current more than this. So for that a resistor is to be placed before the led to oppose the amount of current. The supply voltage coming from the USB is 5V and the current drop at the Light Emitting Diode is 40 milli amperes. The following formula can be used to calculate the resistor value.R=V/Iwhere, the value of V is 5 volts and the value of I is 40 mA.So, R= 5V/0.04A =125 ohmsBut generally, 125 ohm resistor does not exist in real time. Therefore a resistor of 100 ohms is used instead of 125 ohms. Though it gives an output current of 50 mA, this can be tolerated by the LED.How to Operate USB LED Lamp Circuit? Initially connect the circuit as shown in the circuit diagram. Now insert the USB to the port of the computer. You can observe the lamp glowing Now remove the USB from port. Now lamp is switched off.USB LED Lights Circuit Advantages: This is simple and inexpensive. This is a portable lamp. No extra source is required.Applications of USB LED Lamp Circuit: This can be used as an emergency light. Get an idea about Working of Automatic LED Emergency Lights Circuit. This can be used to work with laptop or computer without disturbing the others sleep. This can be used as a reading lamp.Limitations of the Circuit: This gives low intensity of light as it has only four LEDs.Electronics Hub HOME PROJECT IDEAS B.TECH ANDROID FREE PROJECT CIRCUITS ELECTRONICS TUTORIALS MINI PROJECTS CALCULATORS CONTACT US Home Wireless Mobile Battery Charger Circuit Wireless Mobile Battery Charger CircuitJuly 10, 2014 By Administrator 4 Comments Emerging technologies are making our life simpler these days. With the introduction of mobile phones, life has changed rapidly. This is a dream of radio engineering. Mobile phones merged land line telephone systems. These days, many advancements in the mobile phones were introduced. These advancements provide many services such as text, internet etc. But although there are many advancements in the technology, we still rely on the wired battery chargers. Each phone will have its own designed battery charger. Thus the battery chargers are required to carry everywhere to keep the battery backup. Now just think of a battery charger that charges your mobile automatically. When you sit for tea and place your mobile on the table, it simply charges your mobile. This article explains a simple wireless battery charger circuit that charges you mobile when placed near the transmitter.This circuit may be used as wireless power transfer circuit, wireless mobile charger circuit, wireless battery charger circuit, etc.Also get an idea about How to Design a USB Mobile Charger Circuit?Wireless Battery Charger Circuit Principle:This circuit mainly works on the principle of mutual inductance. Power is transferred from transmitter to the receiver wirelessly based on the principle of mutual induction.Inductance is the property of the conductor, in which the current flowing in a conductor induces a voltage or electromotive force in it or in another nearby conductor. There are two types inductance. 1)Self inductance, 2)Mutual Inductance.Self inductance is the phenomena in which when the current is passing in one conductor, an emf is introduced in another coil.Mutual inductance is the phenomena in which, when a current carrying conductor is placed near another conductor voltage is induced in that conductor. This is because, as the current is flowing in the conductor, a magnetic flux is induced in it. This induced magnetic flux links with another conductor. Thus this flux induces voltage in the second conductor.Wireless Power TransferCircuitDiagram:

Wireless Mobile Charger Circuit DiagramWireless Mobile ChargerCircuit Design:Wireless battery charger circuit design is very simple and easy. These circuits require only resistors, capacitors, diodes, Voltage regulator, copper coils and Transformer.In our Wireless battery charger, we use two circuits. The first circuit is used to produce voltage wirelessly. Initially, transformer is used to step down the voltage from 230 V to 12V. This step-down voltage is applied to the diode. The 1N4007 diode is used to allow the voltage to flow in one direction only. This is then passed to the 7812 voltage regulator. The output of this regulator is a 12V DC voltage. Two capacitors are placed before and after the voltage regulator to eliminate the ripples. Next it is connected to the oscillator circuit. It produces a frequency of 10 MHz. The values of resistors and capacitors are calculated in such a way that it produces oscillations of 10MHz. Then it is fed to the inductor. Inductor is used to induce the voltage in the second circuit.In the second circuit, another inductor is used for the mutual inductance. A voltage multiplier circuit is used after the inductor. It is then connected to the voltage regulator 7805.7805 and 7812 are family of 78XX integrated circuit. It produces fixed voltage at the output. 78 represents series and XX represents the output voltage. At the output of the regulator a capacitor is connected. Thus output is connected to the battery.NOTE: Also get an idea about the Battery Level Indicator Project Circuit and its WorkingHow to operate this Wireless Power Transfer Circuit? Initially, connect the circuit as shown in the circuit diagram. Now connect Ac voltage to the transformer. Switch on the supply. Connect the battery charger at the output of the circuit. Make sure that AC and DC sources should not have common connections. You can observe the battery charging at the output.Wireless Battery Charger Circuit Advantages: Usage of separate charger is eliminated. Phone can be charged anywhere and anytime. It does not require wire for charging. Easier than plug into power cable.Wireless Power TransferCircuitApplications: Wireless chargers can be used to charge mobiles, camera batteries, Bluetooth headsets etc. This can also be used in applications like car battery charger with little modification.Go to Simple Car Battery Charger Circuit post for more information. This can also be used in medical devices.Limitations of the Circuit: Power is somewhat wasted due to mutual induction. It will work for very short distances only. If you want to use it forlong distances, then the number of inductor turns should be high.Related Posts Mobile Phone Battery Charger with Emergency Light 0-28V, 6-8A Power Supply Circuit using LM317 and 2N3055 Simple 100W Inverter Circuit Lead Acid Battery Charger CircuitComments1. madhu says: July 13, 2014 at 9:43 am finally connecting to the charger ,either it is a charger or the battery,will you expand itReply Administrator says: July 16, 2014 at 6:35 am Connect the output terminals to charging pin, so that you can charge your mobile.Reply 2. Danula says: July 14, 2014 at 11:07 pm superReply 3. akashdave says: July 22, 2014 at 9:58 am useful website for garib logReply Speak Your Mind Top of FormName *Email *Website

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