This comparator relay board is a simple and flexible solution that can be configured for a wide range of applications, such as automatic light/dark switching, over-voltage and under-voltage protection, over-current and under-current detection, pressure-based switching, temperature control, and interfacing with various analog sensors.
This comparator relay board is a simple and flexible solution that can be configured for a wide range of applications, such as automatic light/dark switching, over-voltage and under-voltage protection, over-current and under-current detection, pressure-based switching, temperature control, and interfacing with various analog sensors.
For 5V applications, the board can be build with the LMV331 comparator in a SOT-23 package. For higher-voltage applications, the TL331 comparator can be used, which supports supply voltages up to 36 V. When operating at 5 V, a 5 V relay is recommended. For higher supply voltages, it is recommended to use a 12 V or 24 V relay.
A trimmer potentiometer is provided to set the reference voltage. The reference can be connected to either the inverting or non-inverting input of the comparator using the provided resistor network. Resistors R6 and R12 are used to configure the upper and lower threshold reference voltages. Resistor R4 can be used to introduce hysteresis and prevent relay chatter near the switching threshold.
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