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Which diode is used with relay?
The use of a diode in a relay circuit prevents huge voltage spikes from arising when the power supply is disconnected. A flyback diode is sometimes called flywheel diode, freewheeling diode, relay diode, or snubber diode as a flyback diode circuit is a type of snubber circuit.
Why use a diode in a DC circuit?
It allows current to flow easily in one direction, but severely restricts current from flowing in the opposite direction. Diodes are also known as rectifiers because they change alternating current (ac) into pulsating direct current (dc). When a diode allows current flow, it is forward-biased.
Why do you need a flyback diode in a relay?
The use of a diode in a relay circuit prevents huge voltage spikes from arising when the power supply is disconnected. A flyback diode is sometimes called flywheel diode, freewheeling diode, relay diode, or snubber diode as a flyback diode circuit is a type of snubber circuit. Why Put a Diode Across a Relay Coil?
What should the reverse voltage of a relay be?
In your relay, the coil current is shown as 79.4 mA. Specify a diode for at least 79.4 mA current. In your case, a 1N4001 current rating far exceeds the requirement. The diode reverse voltage rating should be at least the voltage applied to the relay coil. Normally a designer puts in plenty of reserve in the reverse rating.
Are there voltage spikes on the back side of the diode?
There shouldn’t (in theory) be any voltage spikes on the back/blocking-side of the diode. Although I guess if there were a voltage spike up-stream from the pump/motor I guess it would be better for that to flow through the diode (backwards) rather than the pump.
What kind of diode do I need for digikey?
In your case I’d suggest a 100 V 10 A surge current diode would be more than adequate. A lowly 1N4003 diode would be quite adequate at 140 V reverse voltage and 30 A non-repetitive pulse rating. However something like this Schottky device (even more margin) is only 10-15 cents on Digikey or Mouser.