Precautions For Using Circuit Board Relays

1. When used with AC inductive loads, high transient voltages and surge currents are applied to the output end, which may cause the solid-state relay to conduct or be damaged. It is usually necessary to connect a voltage control device with a specific clamping voltage to the output end, such as Two-wire zener diode or varistor (MOV). It is recommended that the varistor be 1.6-1.9 times the rated voltage.
2. For DC inductive loads, such as solenoids, electromagnets, and electromagnetic valves, a freewheeling circuit must be used to suppress the back 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. A better circuit is a diode and a Zener diode connected in reverse series or a diode connected in series with a resistor and then inversely connected to the load. in parallel.
3. When controlling a smaller current load close to the minimum load current, a virtual load resistor must be connected in parallel to the load to reduce the output leakage current and produce a higher residual voltage on the load.
4. When welding and installing circuit board welding-mounted relays, the welding temperature must be controlled below 260 degrees Celsius, and the welding time must be controlled below 5 seconds.
5. In order to prevent the temperature rise of solid-state relays from exceeding the allowable value, the heat dissipation effect and installation location should be considered during design and application. When two or more solid-state relays are installed side by side, appropriate spacing should be left.