In electronics:
A relay is an electrically operated switch that uses a small voltage/current to turn on/off a larger voltage/current.
They are typically used to reduce costs, in that making all the wiring in a device (house/car/aeroplane etc) able to cope with the maximum voltage/current is expensive.
It is perhaps cheaper to use low voltage/current wires for most of the system, and put in a relay so that the switch you press is then cheap, as it is low voltage, and the wiring is cheap for the same reason. The expensive (heavy) high voltage/current wiring is reduced to a minimum and can be run directly from source to device. To add to that answer:
The relay, normally, is a coil of wire connected to the lower voltage source, through which a metal rod is ran (simple electro-magnet) to conduct the magnetic influence caused by charging the coil of wire. This bar then reacts with a 'reed' (a metal arm, normally sprung or with a spring attached) to cause it to move and 'make' contact between itself and another high voltage source (as explained above). The "contacts" on the end of this reed are normally 'sized' based upon their voltage/current limits and the spring return time is often stated as 'activation time' or 'transition' times.
RELAYS bad'
Both Current and Potential Transformers are used for relays according to the working of relay.
explain cro construction and working
Relays usually go out all at once, but I have seen changes in weather such as humidity cause a relay to work intermittently.
More than likely this is caused by the relays. They are both the same relays and anywhere carries them.
1. Explain the working principle of a milling machine?
Working, working and working.
working of blue tooth
explain how good working relationships can be developed with team members
Explain the workin principle of uln and its abbreviation
That a small amount of power can control a larger load, or can switch an entirely separate load.
have u checked ur relays?