44 lines
1.4 KiB
Rust
44 lines
1.4 KiB
Rust
use crate::quantity::{Ohms, Volts};
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/// Given the resistance of the second resistor in a resistive voltage divider, calculate the resistance of the first resistor.
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pub fn solve_r1(
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voltage_src: Volts<f32>,
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voltage_read: Volts<f32>,
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r2: Ohms<f32>,
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) -> Ohms<f32> {
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Ohms(r2.0 * (voltage_src.0 / voltage_read.0 - 1.0))
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}
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/// Given the resistance of the first resistor in a resistive voltage divider, calculate the resistance of the second resistor.
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pub fn solve_r2(
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voltage_src: Volts<f32>,
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voltage_read: Volts<f32>,
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r1: Ohms<f32>,
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) -> Ohms<f32> {
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Ohms((r1.0 * voltage_read.0) / (voltage_src.0 - voltage_read.0))
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}
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// ---------------------------------------------------------------------------------------------------------------------
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// ----- Tests ------------------------
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// ---------------------------------------------------------------------------------------------------------------------
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#[cfg(test)]
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mod tests {
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use crate::quantity::{OhmsVal, VoltsVal};
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use super::*;
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use float_cmp::assert_approx_eq;
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#[test]
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fn solve_r1_test() {
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let resistance = solve_r1(3.3.volts(), 2.0.volts(), 1_000.0.ohms());
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assert_approx_eq!(f32, 650.0, resistance.0);
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}
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#[test]
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fn solve_r2_test() {
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let resistance = solve_r2(3.3.volts(), 2.0.volts(), 1_000.0.ohms());
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assert_approx_eq!(f32, 1538.462, resistance.0);
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}
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}
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