A pair of simple voltage comparator circuits on one PCB which can be set up to work as two independent circuits or as a combined 'window' comparator.
Handy for use as a simple thermostat, light activated switch or level detector.
Supplied with a pair of temperature sensors and a pair of light sensors to get you started.
Each circuit consists of a simple voltage comparator circuit with a screw terminal input for a sensor of your choice. The circuit has an adjustable multi-turn pot to set the trip point at which the relay switches over. A jumper link selects whether the relay turns on above the threshold voltage or whether the relay turns off at the threshold voltage.
Each circuit operates independently, apart from a shared 12v supply.
The relays are rated to switch mains voltages at currents up to 5A. PCB track thicknesses, clearances and screw terminals are designed for these levels.