Precautions for the use of circuit board relays

1. When used in AC inductive loads, high transient voltage and surge current are applied to the output terminal, which may cause the solid state relay to be turned on or damaged. Usually, it is necessary to connect a voltage control device with a specific clamping voltage at the output terminal, such as Two-wire zener diode or varistor (MOV).

2. For DC inductive loads, such as solenoids, electromagnets, and electromagnetic valves, a freewheeling circuit must be used to suppress the counter electromotive force generated during shutdown. Usually, the simpler method is to connect a diode in reverse parallel with the load, but this The circuit will affect the release time of inductive loads such as electromagnetic relays, contactors, electromagnets, solenoid valves, etc. The better circuit is a diode and a Zener diode in reverse series or a diode in series with a resistor and then reversed to the load in parallel.
3. When controlling a small current load close to the minimum load current, a dummy load resistor must be connected in parallel to the load to reduce the leakage current at the output terminal and generate a higher residual voltage on the load.
4. When soldering and installing circuit board soldering installation relays, the soldering temperature must be controlled below 260 degrees Celsius, and the soldering time must be controlled below 5s.