DC ELECTRICAL CIRCUITS
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DC ELECTRICAL CIRCUITS. METER USAGE. DC ELECTRICAL CIRCUITS. INTRODUCTION. Students will be able to Measure Electrical Quantities. Students will be able to Calculate Electrical Quantities. SEMICONDUCTORS.
DC ELECTRICAL CIRCUITS
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DC ELECTRICAL CIRCUITS METER USAGE
DC ELECTRICAL CIRCUITS INTRODUCTION • Students will be able to Measure Electrical Quantities. • Students will be able to Calculate Electrical Quantities
SEMICONDUCTORS • You will need to be familiar with the basics of your digital multi-meter to successfully test the different components you will be using in your experiments. • The most basic test is a continuity test using the ohms scale typically set to RX-1 or Ω.
SEMICONDUCTORS • Some meters have a chime indicator for continuity tests. • Here we are testing our meter by touching the leads together, we should have a very low resistance (only the resistance of the test leads is indicated.
SEMICONDUCTORS • If we get an “OL” reading something is wrong, OL stands for “open loop” or infinite resistance, it may be necessary to check the fuse if you read “OL”.
SEMICONDUCTORS • Notice the warning, DE-ENGERIZE CIRCUIT FIRST. NO SOUND INDICATES AN OPEN CIRCUIT
SEMICONDUCTORS • Note: we have the same warning!
SEMICONDUCTORS • We set the dial to “V” and then use the button to toggle to “DC”.
SEMICONDUCTORS • When measuring “AC”, select the “V” setting and your meter automatically defaults to AC voltage.
S1 SPST mV V mA A W kW B1 15 V R1 1 kW d c a c COM- +V A W DC ELECTRICAL CIRCUITS Measuring Voltage Connect - lead to - terminal of source Select the dcV function Connect + lead to + terminal of source
S1 SPST mV V mA A W kW B1 15 V R1 1 kW d c a c COM- +V A W DC ELECTRICAL CIRCUITS Measuring Current Select the dc mA function
mV V mA A W kW d c a c COM- +V A W DC ELECTRICAL CIRCUITS Measuring Current Connect the - lead so that electrons enter it Select the dc mA function S1 SPST Physically interrupt the circuit B1 15 V R1 1 kW Connect the + lead to the other point
S1 SPST mV V mA A W kW B1 15 V R1 1 kW d c a c COM- +V A W DC ELECTRICAL CIRCUITS Measuring Resistance Select the kW function
mV V mA A W kW d c a c COM- +V A W DC ELECTRICAL CIRCUITS Measuring Resistance Remove power (open switch) Select the kW function S1 SPST B1 15 V R1 1 kW Connect the leads
DC ELECTRICAL CIRCUITS Measurement Quiz function Select the correct ____ of the meter before measuring an electrical quantity. When measuring voltage, the meter’s positive lead is connected to the ____ terminal of the source. positive negative When measuring current, the meter’s ____ lead receives electrons from the circuit. current When measuring ____, the meter is connected to the points created by interrupting the circuit. Power is removed from the circuit before measuring ____. resistance
S1 SPST B1 36 V R 1.8 kW V R 36 V 1800 W = DC ELECTRICAL CIRCUITS Calculating Current =0.02 A =20 mA I=
A 0.03 A B1 24 V R 24 V 0.03 A V I = DC ELECTRICAL CIRCUITS Calculating Resistance R= =800 W =0.8 k W
A 0.15 A B1 R 270 W DC ELECTRICAL CIRCUITS Calculating Voltage 0.15 Ax 270 W= 40.5 V IR = V=
A V DC ELECTRICAL CIRCUITS 0.2 A Calculating Power 54 V 270 W IV= P = 10.8 W 0.2 Ax54 V= 0.2 A x 0.2 Ax 270 W= 10.8 W P= I2R= P = V2/R= (54 V x 54 V)/ 270 W = 10.8 W
DC ELECTRICAL CIRCUITS Calculation Quiz Determine I when R = 10 W and V = 25 V. 2.5 A Determine R when I = 1.3 A and V = 26 V. 20 W Determine V when R = 15 W and I = 1.2 A. 18 V Determine P when I = 3.3 A and V = 16 V. 52.8 W Determine P when I = 4 A and R = 20 W. 320 W Determine P when V = 8 V and R = 16 W. 4 W