What is a freewheeling diode and what is its purpose?

Definition: Freewheeling diode is used to protect the circuit from unusual damage caused due to abrupt reduction in the current flowing through the circuit. It is also known as Flyback diode and forms connection across the inductor to remove Flyback voltage generated across it.

What is commutation of diodes?

Commutation is the process when conduction switches from one supply phase to another. Commutation overlap occurs when there is inductance in the supply circuit of a diode (or thyristor) rectifier. It can be seen by adding a supply inductance to the 3-phase supply in the diode rectifier simulation.

What is the purpose of a flyback diode?

A flyback diode or freewheeling diode is placed with reverse polarity from the power supply and in parallel to the relay’s inductance coil. The use of a diode in a relay circuit prevents huge voltage spikes from arising when the power supply is disconnected.

What is the purpose of commutation circuit?

The purpose of the commutation cell is to “chop” DC power into square wave alternating current. This is done so that an inductor and a capacitor can be used in an LC circuit to change the voltage. This is in theory a lossless process, and in practice efficiencies above 80-90% are routinely achieved.

What are the advantages of freewheeling diode?

What are the advantage of free wheeling diode in a Full Wave rectifier? It reduces the harmonics and it also reduces sparking and arching across the mechanical switch so that it reduces the voltage spike seen in a inductive load.

How does zener diode works?

A Zener diode is a silicon semiconductor device that permits current to flow in either a forward or reverse direction. The Zener diode has a well-defined reverse-breakdown voltage, at which it starts conducting current, and continues operating continuously in the reverse-bias mode without getting damaged.

What is the purpose of commutating diode?

Commutating diode In electronics parlance, commutation refers to the reversal of voltage polarity or current direction. Thus, the purpose of a commutating diode is to act whenever voltage reverses polarity, for example, on an inductor coil when current through it is interrupted.

Do I need a diode on a relay?

With a transistor output driving a relay, a freewheeling diode is absolutely necessary, because the voltage spike will destroy the transistor. When using a switch to turn on/off a relay, omitting the diode will work, but your switch will be happier when you use a diode (one individual diode for each relay).

What is the purpose of a commutating diode?

In electronics parlance, commutation refers to the reversal of voltage polarity or current direction. Thus, the purpose of a commutating diode is to act whenever voltage reverses polarity, for example, on an inductor coil when current through it is interrupted.

What does commutation mean in an inductor circuit?

Thus, the switch contacts experience a voltage drop equal to the battery voltage plus about 0.7 volts (if the diode is silicon) during this discharge time. In electronics parlance, commutation refers to the reversal of voltage polarity or current direction.

What happens to the diode when the coil is opened?

Thus, when the coil is energized, the diode conducts no current in Figure above (b). However, when the switch is opened, the coil’s inductance responds to the decrease in current by inducing a voltage of reverse polarity, in an effort to maintain current at the same magnitude and in the same direction.

How is a diode similar to a capacitor?

Basically a diode is a junction between two surfaces and so it has an area and a distance in between which also makes a perfect capacitor. A capacitor is a short circuit for high frequency and this will overcome the rectifying characteristic of the junction.