The lowest-cost way to achieve this goal is to use a 1-quadrant unipolar dc supply (Fig. 1a) outfitted with a polarity reversal relay. However, using a polarity reversal relay brings with it three ...

The essence of the circuit is for the input of tone and signal to provide an activation for the relay switch. Relay – an electrically operated switch where the current flowing through the coil of the ...

Last column, I wrote about various applications where fire alarm relays could be used to integrate a commercial fire alarm system with other electrical systems at a customer’s site to provide them ...