CalcOhmsches Gesetz & Leistung
Zuletzt aktualisiert: 2026-05-09
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| Spannung (V) (V) | Strom (ZU) (A) | Widerstand (Ω) (Ohm) | Leistung (W) | |
|---|---|---|---|---|
| Escala laboratorio | 0.4 V | 0.4 A | 0.4 Ohm | 0.4 W |
| Uso domestico | 0.7 V | 0.7 A | 0.7 Ohm | 0.7 W |
| Aplicacion industrial | 1.0 V | 1.0 A | 1.0 Ohm | 1.0 W |
| Ingenieria civil | 1.5 V | 1.5 A | 1.5 Ohm | 1.5 W |
| Escala cientifica | 2.5 V | 2.5 A | 2.5 Ohm | 2.5 W |
Ohm's Law + Power Calculator
Ohm's Law is the fundamental relationship between voltage, current and resistance in an electrical circuit. This calculator solves for any unknown variable and also computes the electrical power dissipated.
Ohm's Law formulas
The basic relationships are:
- Voltage: V = I × R
- Current: I = V / R
- Resistance: R = V / I
- Power: P = V × I = I² × R = V² / R
Knowing any two values (V, I, R), you can compute all others including power.
Example 1: simple circuit
Problem: Voltage V = 12 V, resistance R = 4 Ω.
- Current:
- I = 12 / 4 = 3 A.
- Power:
- P = 12 × 3 = 36 W.
Answer: I = 3 A, P = 36 W.
Example 2: light bulb
Problem: A 60 W bulb connected to 120 V.
- Current:
- I = P / V = 60 / 120 = 0.5 A.
- Resistance:
- R = V / I = 120 / 0.5 = 240 Ω.
Answer: I = 0.5 A, R = 240 Ω.
Häufige Anwendungsfälle
- Designing electronic and electrical circuits.
- Sizing resistors for LEDs and components.
- Computing electrical consumption of appliances.
- Diagnosing faults in electrical circuits.
- Selecting cables based on expected current.
- Solving electricity problems in education.
Common mistakes with Ohm's Law
- Confusing voltage (V) with current (I).
- Not using consistent units (volts, amperes, ohms).
- Applying Ohm's Law to non-ohmic components (diodes, transistors).
- Ignoring that resistance can vary with temperature.
Profi-Tipp
Ohm's Law only applies directly to ohmic components (resistors). For diodes, transistors and other semiconductors, the V-I relationship is non-linear and more complex models are needed.
The ohm (Ω) is the unit of resistance. 1 Ω = 1 V/A. It represents the opposition to the flow of electric current.
Yes, but in AC you use impedance (Z) instead of resistance (R), which includes capacitance and inductance effects.
R = (V_supply − V_LED) / I_LED. For example, with 5V supply, 2V LED and 20mA: R = (5−2)/0.02 = 150 Ω.
It depends on the type. Common resistors are 1/4 W or 1/2 W. If the computed power exceeds this, you need a higher-power resistor.