Hysteresis Comparator Calculator
A hysteresis comparator is a comparator with hysteresis in its transfer characteristic. Adding a positive feedback network to an inverting single-threshold comparator creates an inverting hysteresis comparator with two thresholds. Because of the feedback, the threshold voltages shift with the output voltage.
This calculator computes the resistor ratio R2/R1 and reference voltage from the hysteresis thresholds, or the thresholds from a given ratio and reference voltage.
Note: use a minus sign "-" for negative voltages.
Supply voltage
Direction 1: known threshold voltages → calculate resistor ratio and reference voltage
Direction 2: known resistor ratio and reference voltage → calculate threshold voltages
Hysteresis comparator circuit diagram
Formula
Direction 1: known threshold voltages
R2/R1 = (V+ - V-) / (Vth - Vtl)
Vr = (V- + Vth × R2/R1) / (R2/R1 + 1)
Direction 2: known resistor ratio and reference voltage
Vth = Vr + (Vr - V-) / (R2/R1)
Vtl = Vr + (Vr - V+) / (R2/R1)
Parameter descriptions
- V+ / V-: positive/negative supply voltages
- Vth: high threshold voltage
- Vtl: low threshold voltage
- Vr: reference voltage
- R2/R1: feedback resistor ratio
How to use:
• Click "Calculate →" to compute the resistor ratio and reference voltage from the known high/low threshold voltages
• Click "← Calculate" to compute the high/low threshold voltages from the known resistor ratio and reference voltage
• The two calculation directions can be used independently