Debugging a "Broken" Circuit
The left circuit works correctly.
The two connected 1.25 K resistors in the middle are equivalent to a 2.5 K resistor.
The middle circuit:
The unconnected two 1.25 K resistors in the middle "simulate" a cracked (in half) 2.5 K resistor. (Or, possibly a broken circuit board pad or trace.)
Notice:
All 20 V are measured on middle voltmeter.
And, there is 0 V drop across R1 and R4!
The right circuit:
The two connected 1 micro ohm resistors in the middle represent a "short" in the circuit.
Notice:
Higher overall current flow due to lower total resistance.
Higher voltage drops across R1 and R4.
And, approximately a 0 voltage drop across R2 plus R3!
