The RF1 series relay provides compact solid-state switching and is suitable for confined-space applications that require operation for a large number of cycles. The zero-switching type (RF1A) switches ON when the voltage crosses the ac sine wave’s zero crossover point. The instant-ON type (RF1B) switches on at the instant when control voltage is applied. Integrated transils provide protection against over-voltage. A green LED indicates the presence of control voltage. Fast-on terminals for the input and output voltage enable fast and secure installation.