SSR SOLID STATE RELAY 1 CHANNEL
DC+:Connect power positive
DC-:Connect power negative
CH:Relay module signal trigger end(Low level trigger is effective)
Wiring: When the triggered by low voltage, current will get through
A solid state relay (SSR) is an IC that acts like a mechanical relay.
SSR consist of a sensor which responds to an appropriate input (control signal), a solid-state electronic switching device which switches
power to the load circuitry, and a coupling mechanism to enable the control signal to activate this switch without any mechanical parts.
The main parts of a standard SSR is:
A SSR is based on a single MOSFET, or multiple MOSFETs in a paralleled array. It has an inherent substrate diode that conducts in the reverse direction, so a single MOSFET cannot block current in both directions. For AC (bi-directional) operation two MOSFETs are arranged back-to-back with their source pins tied together. Their drain pins are connected to either side of the output. The substrate diodes are alternately reversed to block current when the relay is off. When the relay is on, the common source is always riding on the instantaneous signal level and both gates are biased positive relative to the source by the photo-diode.
Solid state relays, have several advantages over mechanical relays:
1.) SSR can be switched by a much lower voltage and at a much lower current than most mechanical relays.
For example, the above SSR module can be driven only by 5mA current, while most the mechanical relay would need a minimum drive current 100mA;
2.) Much faster switch speed; the minimum switch time of SSR can be up to 1ms; while most the mechanical relay needs 10 ms at least;
3.) As the SSR do not have any moving parts, it would be more stable in hard environments and have a longer lifetime;
4.) Totally silent operation, no Relay chatter noise in the switching anymore;
SSR works as follow picture. When there is no signal in the input, the output terminal disconnected;
when the input signal be active, the 2 outputs of the SSR connected so the whole load circuit connected: