adjustable constant current source 4ma to 3a

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Adjustable constant current source 4mA to 3Aby Jan_Henrik on December 17, 2013

Table of Contents

Adjustable constant current source 4mA to 3A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Intro: Adjustable constant current source 4mA to 3A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Step 1: Part list . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Step 2: Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Step 3: Assembling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Step 4: Testing (yay :D) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Step 5: Final Step! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Related Instructables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Advertisements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6


Intro: Adjustable constant current source 4mA to 3AHello, in this project i want to show you aadjustable constand current source, wich maximal current is 3A by 39V. This is a very usefull circuit, to light up power LEDs orheater, also it is a very cheap and tiny circuit, which is easy to build. For the project you need basic soldering skills and basic elektronic skills.Features:

Current range: 4mA to 3AVoltage range: 1,2V to 35VTemperature range: +-0C to +125CSize: 4cm x 3cm x 5cmCosts: 1$ to 5$

Image Notes1. Adjustment wheel2. Terminals

3. Lm3504. Heatsink

Step 1: Part listParts:

LM350 (or Equal)Heatsink for the LM350Terminalscircuit boardPotentiometer 15OHM 1W, 2W or 5WWireUnisolatet wire

Tools:

Soldering coilSolderScrewdriver

Other:

power Supplymaybe a 10W LED or a 5W 2,7OHM Resistor for testinga multimeter


Image Notes1. Potentiometer 10OHM 1W2. Wire3. Terminals4. LM3505. Heatsink6. Table :>

Step 2: CircuitThe circuid is veeery simple, you only have to wire 2 electronic components and 2 terminals. be carefull with the LM350, dont confuse the pins!

Image Notes1. In2. Adjust3. Out


Step 3: AssemblingNow assemble it, make sure that you got thick wire for the circuit board and the potentiometer because there can be currents about 3A. Also make sure that everything isgood soldered and the heatsink is good connected to the lm350! also dont forget to mark the terminals with "+ - input and output"

Image Notes1. Adjustment wheel2. Terminals

3. Lm3504. Heatsink

Image Notes1. Output -2. Input -3. Input -4. Input5. LM3506. Connectors for the variable Resistor.7. Pins of the variable Resistor

Step 4: Testing (yay :D)For testing you need a power supply (i prefer for that 12V), a multimeter, a resistor 2,7OHM 5W (!!!), and wires.now connect the positive output of the constant current circuit to the 2,7OHm 5W Resistor, switch your multimeter to ampere measurement and connect the positiveprobe to the other side of the resistor.

Next connect the negative probe to the negative output of the constant current circuit.

!!! DONT short circuit parts of the circuit and DONT short circuit it with your FINGERS!!!

Regulations the potentiometer to the middle position!!!

now connect the power supply to the input of the circuit, turn it on and regulate it to 12V.

If you twist the potentiometer the multimeter should show the floating current, which should be from 0mA to 1,3A - SUCESS!

But why 1,3A i told it could reach 3A... it can you just have to regulate up the voltage, then the current should rise.

The output Voltage should be 0,7V lesser the the Input voltage.


Image Notes1. 1,082A2. 1,082A3. Other 1W 10OHM potentiometer4. 2,7OHM 5W resistor

Image Notes1. 0,028A2. 0,028A

Step 5: Final Step!Troubleshooting:

errors could be:

confused the pins of the LM350short circuitselectronic components burned out

Uses:

HeatersHeating pad for 3D printersHigh current LEDscurrent limit

Thank you for reading! :)i hope you like it, feel free to comment


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adjustable constant current source 4ma to 3a

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