If a branch of a circuit contains a resistor, the best way to measure the current in that branch is to measure the voltage across the resistor and divide by R. However this gives a value which is only as accurate as the value of R. Consequently, start this investigation by accurately measuring the values of all resistors which will be used.
Of course if a branch of a circuit contains no resistors, the current in that branch must be measured directly with a milliammeter (or else deduced by Kirchoff's current law from other known currents.)
Set up the circuit in Figure 1. Use the +25 volt output for VS1 (set to 10 volts) and the 6 volt output for VS2 (set to 6 volts.) Set the current limits to 100mA. Use the DMM for measurements.
IMPORTANT: Please reduce the resistor values by a factor of 10.
SO, use 100, 470, 680, and 1000 Ohm resistors for the circuit instead of the indicated values on the circuit diagram.
Figure 1.
Make the appropriate measurements to verify KVL around loops 1, 2, and 3, and the perimeter of the circuit. (You will find that you must understand the sign convention for voltages, and you must understand what the DMM tells you about the sign of a measured voltage, in order to do this.) Record the measurements and comment on the accuracy with which KVL is verified for these four loops.
Make the appropriate measurements to verify KCL at nodes A, B, C, and D. (As before, you must understand signs! The DMM counts current as positive if it enters the mA terminal and leaves the COMMON terminal.) Record and comment as for the KVL experiment.
Calculate the power absorbed by all elements in the circuit, including the sources. Add these up and comment on the degree to which your measurements confirm the fact that the total power absorbed in the circuit is zero.
Repeat part II, but replace VS1 with the function generator, set for 10cos(2000pit). Make the voltage measurements with the DMM and with the scope. Make the current measurements with the DMM. Skip the power calculations.