# EE188L EE I Laboratory Lab #2 Resistive Circuits.

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EE188L EE I Laboratory Lab #2 Resistive 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 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 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 = DMM Can measure voltage, current, resistance, and diode turn-on voltage Gives digital readout

Measuring Resistance with the DMM 1. Red probe is in correct position 2. Make sure the button with  is pressed 3. Place red and black probes on two terminals when not connected to power 4. Read value of resistance on display and note the units

Measuring DC Voltage with the DMM 1. Red probe is in correct position 2. Make sure the button with V= is pressed to measure DC voltage 3. Place red and black probes on two nodes 4. Read value of voltage displayed and note the units 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 circuit 2. 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 current 4. Read value of current flowing into red probe on display and note the units

Measuring DC Current with the DMM 1 DMM connection is tricky Open circuit and insert DMM Reading is current flowing into red probe

Resistor Color Code http://www.elexp.com/t_resist.htm 56 * 10 k  = 560 k  237 * 1  = 237 