How does a flyback diode work?

How Does a Flyback Diode Work?

  1. A flyback diode is a diode connected across an inductor.
  2. A changing magnetic field through a coil of wire will induce an emf in the coil which in turn causes current to flow, even after the switch is opened.
  3. As shown in figure 2, it will take τ for the current to decrease from 99% to 37%.

How do you set a flyback diode?

Usually, the flyback diode is selected so that there is plenty of reserve in the reverse voltage rating. The flyback diode current rating should be at least the coil current or working current. Putting reserve in the current rating is followed in flyback diode selection.

Where do we use flyback diode and why?

Flyback diodes are commonly used when inductive loads are switched off by semiconductor devices: in relay drivers, H-bridge motor drivers, and so on.

Why do we need a flyback diode?

The use of a flyback diode in a relay circuit prevents huge voltage spikes from arising when the power supply is disconnected. They are sometimes called a flywheel diode, freewheeling diode, relay diode, or snubber diode.

Do all inductors need flyback diode?

Yes, required. Every inductor, whatever its rating, is a energy storing device. While switching off we need to discharge it, for that we are going to use flyback diode. The diode should be selected based on the maximum operating voltage and current through the inductor.

What size diode do I need for 12V relay?

The relay is rated at 12V dc coil with 240V contacts ,, then a 1N4007 type diode will do.

What is another name for a flyback diode?

In this tutorial, we will learn about one of the major applications of a PN Junction Diode as a Flyback Diode or Freewheeling Diode. The diode is such applications may also be called as Suppression Diode, Snubber Diode, Kickback Diode, Clamp Diode etc.

Can zener diode be used as flyback diode?

This potential can be completely avoided by using a Zener diode in series with a flyback diode. When the switch is opened, the inductor current is shunted through this series arrangement, maintaining voltage equal to the Zener voltage, plus the flyback diode provides current until the inductor energy is dissipated.

Do automotive relays have flyback diodes?

You do not need a flyback diode with all automotive relays.