Features: 5A over-current protection sensor module. Uses current transformer to collect the AC signal to achieve the relay over-current signal output within 0-5A. Relay pull while over-current, relay released while not over-current. Users can use the relay COM, NC, NO three ports to control the external circuit on and off, in order to achieve over-current protection. Over-current signal setting critical point is adjustable. Specification: Type: 5A 5V Relay Module Working voltage: DC5V Working current: <20MA Operating frequency range: 20Hz-400Hz Output mode: switch signal output Maximum detection wire diameter: 5.2mm Mounting hole: hole diameter is 3mm, hole pitch is 52.5mm Operating environment: -40℃ - 85℃ Current detection range: AC0.3A-5A Board size: Approx. 38 * 44mm / 1.5 * 1.7in Weight: Approx. 27g Package list: 1 * Module Functions: Current detection resolution can change the parameter of resistance parameters. Output over-current switching signal output. Over-current signal setting critical point is adjustable. Board Description: VCC: Operating voltage positive; GND :Operating voltage negative; NO: Normally open, the relay pulls before the NO and COM disconnect, short-circuit after the suction; COM: common, relay common interface; NC: Normally closed, the relay before the NC and COM short-circuit, after pull off. Using Instructions: By setting the potentiometer to set the overcurrent protection point, the clockwise adjustment can reduce the detection current. As bellows: 1. Measured the wire through the current transformer , connect VCC and GND to DC5V power supply; 2. Adjust the potentiometer, when you hear the sound of the relay pull (can be measured with a multimeter, to see if COM and NO was turned on, and if connected to the relay means activated), then reduce or cut off the current flowing that through the tested wire , if the relay release at this time that over-current protection point has been identified (can use multimeter to see if COM and NC was connected, if connected to the relay means been released); 3. When reduce or cut off the current flowing through the wire , the relay is not released, will still need to continue to adjust the potentiometer to find the over-current protection point. .