The diode in the circuit is provided for
The diode in the circuit is provided for
A. Reducing the response time
B. Protecting the coil
C. Shunt path
D. Protecting the drive circuit
Please scroll down to see the correct answer and solution guide.
Right Answer is: D
SOLUTION
A schematic for a freewheeling diode circuit in a relay is shown below. The diode provides a path with low resistance that reroutes the current, thus the voltage spike at the downstream load to be much lower.
The current path in the diode depends on whether the switch in the relay is closed or opened.
As the switch is initially closed, the inductor load generates a back electromagnetic field as its transient response, and the voltage slowly rises to the supply voltage value.
Once the switch is opened, the back emf created by the inductor switches direction and points towards the ground, creating a transient response that slowly dies off.
The low resistance loop created by the freewheeling diode in forward bias, the current is diverted through the diode rather than creating a large voltage spike elsewhere in the circuit.
Therefore, the diode is used to protect the drive circuit.