Solid state relay - S202S02

From bildr

Manufacturer: Sharp
Voltage: 1.2 - 1.4

The S202S02 is a solid state relay (SSR) capable of switching up to 8A at 240V. The S202S02 uses an IR LED to switch a Phototransistor connected to a TRIAC. The control and switching sides are completely separated, and no problems should occur between the two sides below 8000v (according to doc sheet).

Hooking it up

Simply powering (1.2v - 1.4v) the S202S02 will switch the relay on. Because the S202S02 uses an IR LED, voltages above 1.4 should not be used because it will quickly burn it out. A resistor may be used when supplying a higher voltage. Based on the doc sheet, a 180 ohm resistor should work when using a 5v supply voltage.

The S202S02 is not suitable for switching DC power. Because of its use of a TRIAC, if this is used to switch on a DC circuit, once switched on, you will not be able to switch it off. This because, a TRIAC, once triggered, will continue to stay triggered until the circuit it has switched on has switched off.

The above problem does not occur when switching an AC circuit because it is constantly fluctuating between on and off, and the S202S02 will act just like a notmal relay turning on and off when voltage is supplied or taken away on the control side.