Why is the minimum load current for most Solid-state Relays specified at 0.1 A?

For triac and thyristor output elements to stay ON, a small amount of current flow (called the holding current) is required. Considering the added effect of the ambient operating temperature, the output element may not be able to stay ON if the load current is less than 0.1 A. This may cause oscillations to appear in the output, or for it to not turn ON at all.

Solid-state Relays typically have less than 10 mA or leakage current at 200 V. To prevent the leakage current from causing load reset errors, the reset current is estimated to be at least 10% of the rated current, and the minimum load current is specified at 0.1 A.

For example, if a load with a rated current of 50 mA is used and the OFF leakage current is 10 mA, the load current would be 20% of the rated load. Depending on the load, this may cause a reset error.

Power MOS FET Solid-state Relays do not require a holding current, and feature small leakage currents. The minimum load current required for Power MOS FET Solid-state Relays to operate normally at 200 VAC is 100 µA.