EE188L EE I Laboratory

Lab #2Resistive Circuits

Objectives of Lab #2

Understand series and parallel connections

Understand the protoboard and Digital Multimeter

Measure and calculate equivalent resistance

Measure voltage difference between nodes

Overview of Lab #2 Activities

Connecting 4 identical resistors together

Putting different resistors in series

Putting different resistors in parallel

Protoboard

Good for making prototype circuits

Note: POWER ON button

3 power supplies +5, +15 and -15 volts

White grid•Holding devices•Making connections Some underneath Some with wires

Simple Circuit Wiring Example

+5 V 1 k

Red wire

Black wire

Useful hints to make connections to power supplies Unscrew plastic nut of power connections Insert wire in hole in post and tighten nut Don’t tighten only onto the wire’s insulation

Protoboard Power Supplies

+5 V +15 V -15 V

+5V at1.0 AMP

+15V at0.5 AMP

-15V at0.5 AMP

3 power supplies with common ground• Must connect between ground and one red terminal• Shows maximum current available

Do not short terminals together! Note fuse on side.

Protoboard Connections

Connections underneath:

•Long rows across the top is connected

•Each row of 5 is connected

•Each column is connected

Digital Multimeter = DMMCan measure voltage, current, resistance, and diode turn-on voltage

Gives digital readout

Measuring Resistance with the DMM

1. Red probe is in correct position2. Make sure the button with is pressed3. Place red and black probes on two terminals when not connected to power4. Read value of resistance on display and note the units

Measuring DC Voltage with the DMM

1. Red probe is in correct position2. Make sure the button with V= is pressed to measure DC voltage3. Place red and black probes on two nodes4. Read value of voltage displayed and note the units

+ 5.06 V -Red probe Black probe

Note 5.06 has 3 significant figures and 5.064 has 4 significant figures.

Measuring DC Current with the DMM 2

1. Connect DMM in series in the circuit2. Red probe is in one of current ports (100ma max or 10A max)3. Make sure the button with A= is pressed to measure DC current4. Read value of current flowing into red probe on display and note the units

5 VResistorNetwork

DMM

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Measuring DC Current with the DMM 1

DMM connection is trickyOpen circuit and insert DMMReading is current flowing into red probe

5 VResistorNetwork

DMM

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Resistor Color Code

http://www.elexp.com/t_resist.htm

56 * 10 k = 560 k

237 * 1 = 237