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What is done to prevent spike in an inductive circuit when the switch opened?
An inductor connected to a switch generates high uncontrolled voltages. We protect nearby components from damaging high voltage by putting a diode in parallel with the inductor.
Can an inductor increase voltage?
An easy way to generate a higher voltage from a low voltage DC source is with an inductor. Depending on the number turns of wire in the coil a 6 volt battery could produce a jolting 200V plus from a simple coil of wire.
When the current to a solenoid or relay is disconnected the magnetic field collapses and causes?
It should be noted that, when we de-energise a relay or solenoid by switching off the supply to the switching coil, the associated magnetic field around that coil will suddenly collapse.
How are voltage spikes suppressed in a relay?
There are 2 devices that can generate spikes. The relay coils. The diodes in anti-parallel will help suppress the spikes when the relays are turned off (The stored energy in the magnetic field is converted back into voltage/current causing a spike that may be inductively and capacitively coupled back in to the mains).
How is the voltage spike affected by inductance?
The voltage spike is influenced by the inductance (the higher the inductance, the higher the voltage spike) as well as the switch-off time and method. The switch-off spike is the highest when a device is quickly electronically disconnected (snap-action) and there is no spike-limiting circuitry.
What causes a voltage spike in a transformer?
For that purpose an AC/AC transformer (240VAC to 6VAC and later rectified and regulated to 5VDC) and wall socket are fed from the same mains socket. The problem is that when the relays are engaged or disengaged it causes a voltage spike which can be heard through speakers attached to the same mains socket.
When do you turn off the relay coils?
If the relays close or open when the maximum current is being drawn you have a similar situation as turning off the relay coils.