Problem ID: 87
Problem Filename: thev_box_ex3
Keywords:
Circut Description:
- Black Box
- Variable Resistor
- Switch
Analysis Method:
- Thèvenin Equivalents
- Voltage Divider
Math Method:
- Algebra
Thèvenin Equivalents
Black Box Terminal Behavior
Problem #3
Consider the following experimental method to measure the Thèvenin resistance of a linear circuit:
(1) With the pushbutton open, measure and record Vm, (2) press the pushbutton and adjust Rvar until Vm is half the original voltage, and (3) release the pushbutton and measure Rvar.
Explain why the measured resistance Rvar is actually the same as the Thèvenin resistance Rt.
Need a hint?
Model the black box as a Thèvenin equivalent. Notice that a voltage divider appears. Write a voltage divider equation for Rvar and solve for Rvar.