The DC version of the SSR was great for applications that provided a DC voltage as the control voltage for switching. But there was also a growing demand from industries that used an AC voltage as its control voltage. From this industry demand, the optically isolated SSR that could accommodate such a voltage was introduced, the AC solid state relay.

Now, mains AC control signals could also be sued to switch higher current hungry circuits. Opto 22 SSR family became a standard in industry, for not only its ease of use but its proven reliability. This reliability provided the company to offer an unprecedented warranty at the time, and is still provided today – a Lifetime Guarantee! Should an Opto 22 SSR fail in service, it will be replaced with a new one for FREE!