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Why are transient suppressors needed on relay coils?
Its purpose is to suppress coil transient voltages. These transient voltage spikes can be many times greater than the source voltage that the coil was energized with. They can damage equipment if large enough and cause arcing in switching devices that will degrade the contacts and cause premature failure.
Do relay coils need a resistor?
1 Answer. You only need a resistor in series with your relay coil if your are applying a voltage that is different than what your relay coil is rated for. At the rated voltage, the coil resistance will be sufficient to limit the current to the levels necessary to energize the coil.
Is a resistor and relay the same?
Relays allow for a high current flow circuit to be controlled by a low current flow circuit, and they are made to fit a variety of applications. Some common relays include the relay with resistor, which will fit into a standard fuse box. The ISO 280 Micro relay with resistor is a smaller version of the standard relay.
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?
How is coil suppression used in a relay?
The suggested technique for relay coil suppression is to used a reverse biased rectifier diode and a series zener diode in parallel with the coil. This permits the relay to have optimum release dynamics and a good contact life. Whenever current flow through a coil of wire stops, a voltage spike is created.
When to use a Zener diode as a flywheel diode?
The answer to When/why would you use a Zener diode as a flywheel diode (on the coil of a relay)? touches on this slightly, by showing a regular Diode in the above left configuration, while showing a Zener Diode in the right configuration.
Why do you need a catch diode on a coil?
Adding a simple catch diode will prevent any significant voltage from appearing on the solenoid or relay when it is released. It will also, however, cause the coil to remain magnetized for much longer than it otherwise would.