| VT (Source) | - |
| R1 | - |
| R2 | - |
| R3 | - |
| Switch | - |
Calculate total resistance and current:
Calculate expected voltage across each resistor:
Select two test points to measure between them.
Select the fault type for each component (may be multiple faults):
One single current path. Current is identical everywhere. Voltage divides.
Current: IT = I1 = I2 = I3Resistance: RT = R1 + R2 + R3Voltage: VT = VR1 + VR2 + VR3
V = I × R I = V / R R = V / I
| Symptom | Open Circuit | Short Circuit |
|---|---|---|
| Current (I) | 0 A (everywhere) | Higher than normal |
| Voltage across faulted component | Full VT | 0 V |
| Voltage across healthy components | 0 V | Higher than normal |
| Total resistance (RT) | Infinite (OL) | Lower than normal |
Match the precision of your least-accurate input.
Example: 12 V ÷ 470 Ω = 0.026 A (2 sig figs — same as “12”)
1. Calculate expected values first (RT, IT, VR1, VR2, VR3)
2. Measure total voltage VT
3. Measure each resistor voltage
4. Compare measured vs calculated
• All match → healthy circuit
• I = 0, one component has full VT → open there
• One component has 0 V, others have higher V → short there
You correctly identified the circuit condition.