Ohm's Law Voltage Calculator
Calculate Voltage, Current, and Resistance while checking for power dissipation limits. Includes AWG ampacity safety warnings.
Voltage: V
Power: W
About
Ohm's Law is the foundation of electronics, but calculating voltage (V = IR) is only half the battle. A common engineering pitfall is ignoring Power Dissipation (P = VI), which leads to burnt resistors and melted wires.
This calculator not only solves for the unknown variable but immediately cross-references the result against standard component ratings (0.25W, 0.5W) and wire ampacity limits, flagging potential thermal failures before you solder a single connection.
ohm's law
voltage
current
resistance
power
Formulas
Voltage:
V = I × R
Power (Heat):
P = V × I = I2R
Reference Data
| AWG Size | Max Amps (Chassis Wiring) | Max Amps (Power Transmission) |
|---|---|---|
| 10 | 55 A | 15 A |
| 14 | 32 A | 5.9 A |
| 18 | 16 A | 2.3 A |
| 24 | 3.5 A | 0.57 A |
| 30 | 0.86 A | 0.14 A |
Frequently Asked Questions
If a resistor dissipates more power (Watts) than it is rated for, it will overheat, change resistance value permanently, and eventually burn open or catch fire. Always use a resistor rated for at least 2x the calculated power.