R-Calc is a tool designed to calculate resistor networks aiming to approximate a given equivalent resistance as closely as possible.
Suppose you require a 608kΩ resistor, but the closest available option in the E24 resistor series is 604kΩ. R-Calc can help find combinations of resistors to achieve a resistance close to 608kΩ:
| Resistor combination | = | deviation |
|---|---|---|
| 620kΩ | 620kΩ | 1,9% |
| 620kΩ ∥ 30000kΩ | 607,446kΩ | 0,091% |
| 1kΩ + 47kΩ + 560kΩ | 608kΩ | Exact |
R-Calc iteratively combines two and later on three resistors, trying to find the closest value to approximate a target resistor. Once an exact approximation is reached, further calculations are unnecessary as additional resistors will not improve the approximation.
Maybe, some time, this tool will also be able to calculate on networks with 4 resistors but this might take a while to implement and currently 3 resistors seem to be good enough for most purposes.