delabs Circuits

Saturday, July 26, 2014

What is a Relay - Jim Asks

(A text chat in Google talk long ago from my email records - 2007)

Jim: hello, anantha.
delabs: hello

Jim: i have a Small problem,it's about would u pls give me an information about relays,pls give different types of relays and their differences.

delabs: for what do you want to use the relay for.

What is a Relay - Jim Asks

"A Relay is an electrically operated switch. Many relays use an electromagnet to mechanically operate a switch, but other operating principles are also used, such as solid-state relays" - Wikipedia

Jim: Two door alarm settable for close or open door

delabs: there is a control signal and an output for relay, if you are using just a buzzer for alarm, no relay needed if you want to operate a big hooter or 230V lamp a relay is needed- or even a motor or solenoid to move some thing  Even a Solid State Relay can be used.

Bigger loads like large motors may need drives and containers. Some even have speed control. Big doors are more difficult to open and close. safety features needed.

The picture above shows also reed relays that are used for small signals - analog and telecom. In Solid State switching also we have small signal and power switches, using mosfet or triac.

Soldermans Basic Electronics: Relays and Contactors

Jim: let me check dis addr nd i'll get back 2 u just now.
Jim: ok but if i have a problem i'll get back 2 u,bye