To help prevent overvoltage problems, a varistor is connected between the ___ terminals of an SSR.

A varistor is a voltage-dependent resistor widely used for protecting circuits from overvoltage transients by clamping voltage spikes to a safe level. In the context of a solid-state relay (SSR), the varistor is typically connected between the output terminals.

Connecting a varistor to the output terminals of an SSR is crucial because the output side is where the load is connected, and it is also exposed to potentially harmful voltage transients that could occur due to fluctuations in the supply, inductive loads, or other electrical interferences. By clamping these voltage spikes, the varistor prevents excessive voltage from reaching the load and potentially damaging both the load and the SSR itself.

On the other hand, the input terminals are associated with the control side of the SSR, which does not directly experience the load voltages. Ground terminals serve to stabilize the circuit and provide a reference point, while the control side is responsible for switching the SSR on or off but lacks the same level of exposure to overvoltage scenarios that might occur on the output side. Thus, positioning the varistor at the output effectively safeguards the entire system against transient overvoltage conditions.