# Crate resistor_calc[−][src]

A resistor value optimiser for circuit design.

When provided with a set of constraints and relations for a series of resistors R1, R2, ..., it can present sets of values from standard series in order of increasing inaccuracy.

# Example

Given the following resistor network:

Where VADJ must remain at 0.8v, as R2 varies from no to full resistance, VOUT varies from 6v to 12v

We can then describe the problem via the following constraints, plus a few extra bounds to eliminate either very small, or very large values, both of which may cause current issues.

```extern crate resistor_calc;

use resistor_calc::*;

fn main() {
let rcalc = RCalc::new(vec![&E24, &E6, &E24]);

println!("Number of combinations: {}", rcalc.combinations());

let res = rcalc
.calc(
ROpBuilder::new()
.bound("R1+R2+R3 <= 1e6")
.bound("R1+R2+R3 >= 1e4")
.bound("0.8 * (1 + R1/R3) ~ 6.0")
.bound("0.8 * (1 + (R1+R2)/R3) ~ 12.0")
.finish(),
)
.expect("Error: No values satisfy requirements");

res.print_best();
}```

Running this example produces the results:

``````Number of combinations: 1185408
Match 1:
Error: 0.000
Values: R1: 13K, R2: 15K, R3: 2K

Match 2:
Error: 0.000
Values: R1: 130K, R2: 150K, R3: 20K
``````

## Structs

 E3 RSeries constant for the E3 standard series E6 RSeries constant for the E6 standard series E12 RSeries constant for the E12 standard series E24 RSeries constant for the E24 standard series RCalc Main calculator struct ROpBuilder Builder struct used to create `f` values for `RCalc::calc` from mathematical expressions. RRes Stores the result of a calculation. RSeries A series of resistor values, constants are provided for standard resistor array values. RSet A binding of values to the set of resistors in a calculation.