Relay
This page covers relay basics and mention relay manufacturers.
A relay is a switch operated by an electromagnet. It is useful of we want a small current in one circuit to control another circuit housing a device e.g. a lamp or a electric motor. Figure depicts relay symbol.
When the controlling current passes through the coil, the soft iron core will get magnetized. This action attracts the L-shaped soft iron armature. This rocks on its pivot and opens, closes or changes over. This way electrical contacts in the circuit can be controlled.
The current requires to operate a relay is called pull in current. The drop out current is the current in the coil when the relay just stops working.
For example, If coil resistance of relay is 190 Ohm and operating voltage is about 10 volt,
Then pull in current of the relay is ,
I = V/R = 10/190 = 0.052 Ampere
Relay manufacturers
Following are reputed relay manufacturers.
• American Relays Inc. manufactures high voltage power relays
• Altech Corp manufactures safety relays
• Aleph International Corp.
• American Electronic Components Inc. manufactures large current relays.
• Comus International
• Clare manufactures reed relays
• Celduc Group
• Finder relays Inc. {Power relay - Monitoring relays}
• Greenwich Electronics Inc.
• Hamlin
• Hasco Components International Corp.
• Leach International Corp.
• MEDER electronic
• NTE Electronics Inc.
• Panasonic Electric Works
• Phoenix Contact
• Pickering Electronics
• Schneider Electric
• Teledyne Relays
• Tyco Electronics
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