BALKE WORKBENCH / IOT & ELECTRONICS
Voltage divider.
Two resistors. One output. See what changes when you connect a load.
Decode color bands with the Resistor Calculator →AUTOMATIC RESISTOR SELECTION
Find both resistors
Enter your input voltage, desired output, and target current through the unloaded divider. Both resistors and nearby standard pairs update automatically.
Ideal values: R1 = 20 kΩ · R2 = 10 kΩ
R1 = (Vin − Vout) / I · R2 = Vout / I. Ideal power: R1 3.2 mW · R2 1.6 mW.
| R1 / R2 | Output / error | Current / error | Power R1 / R2 | Use pair |
|---|---|---|---|---|
| 20 kΩ / 10 kΩBest nearby match | 4 V0.000% | 400 µA0.000% | 3.2 mW / 1.6 mW | |
| 20 kΩ / 9.1 kΩ | 3.7526 V-6.186% | 412.37 µA3.093% | 3.401 mW / 1.5475 mW | |
| 20 kΩ / 11 kΩ | 4.2581 V6.452% | 387.1 µA-3.226% | 2.9969 mW / 1.6483 mW | |
| 22 kΩ / 10 kΩ | 3.75 V-6.250% | 375 µA-6.250% | 3.0938 mW / 1.4063 mW | |
| 22 kΩ / 11 kΩ | 4 V-0.000% | 363.64 µA-9.091% | 2.9091 mW / 1.4545 mW |
Compares combinations of the seven nearest values for each resistor. Ranking balances voltage and current percentage errors equally using √(voltage error² + current error²). Errors are relative to your targets.
Current here means current through R1 and R2 with no load attached. Apply a pair below, then connect a load to see the actual output; this does not size a regulated power supply.
Your circuit
LIVE DC MODELEdit the values beside the circuit. Resistances accept 4K7, 10k, 1M, or plain ohms.
The load is in parallel with R2. A lower load resistance pulls the output down.
UNLOADED DIVIDER
Output voltage
33.333% of Vin
Connect the load to compare its effect. With the example values, a 10 kΩ load changes the output from 4 V to 2.4 V.
- Divider current
- 400 µA
Power dissipation
| Component | Unloaded |
|---|---|
| R1 | 3.2 mW |
| R2 | 1.6 mW |