☑ Use Of Diode In Relay Circuit

This relay circuit just replaces the emitter resistor with the relay coil. The following schematic shows the basic circuit.

Relays Especially The Diode An Introduction To Using

One Day Computer Interface Workshop Relays

Reverse Current Protection Using Diode

The diagram shows how a signal diode eg 1n4148 or 1n4001 or 1n4007 is connected backwards across the relay coil to provide this protection.

Use of diode in relay circuit. This diode is required to protect the 555 timer ic from any back current that might be created within the relays coil when the coil is energized. Protection diode for relay. Whilst the common emitter relay circuit will be the most popular it is sometimes useful to use a common collector or emitter follower configuration for the relay circuit.

Note the diode thats placed across the relay coil in this circuit. The use of a diode in a relay circuit prevents huge voltage spikes from arising when the power supply is disconnected. The diode prevents relay from arcing by giving a return path for the energy stored in the magnetic field of coil extending the life of relay.

Relay coils produce brief high voltage spikes when they are switched off and this can destroy transistors and ics in the circuit. Connect the relay with hc11 port pins this is used to control on switches. The transistor allows the hc11 to control the medium sized coil current of relay.

Again the diode is incorporated into the relay circuit to prevent damage from the back emf induced at turn off. To prevent damage you must connect a protection diode across the relay coil. Because of electromagnetic induction relay coils are prone to this problem.

A flyback diode is sometimes called flywheel diode relay diode or snubber diode as a flyback diode circuit is a type of snubber circuit. The base resistor is placed in the circuit to limit the base current although in many instances this may not be required. Protection diode in the circuit transistors and ics must be protected from the brief high voltage produced when a relay coil is switched off.