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k7elp60 said:Russlk is correct, but I would like to add that when the field collapses the polarity of the voltage is opposite, that is why the diode is installed the reverse polarity of the energizing voltage.
gerty said:One effect of NOT using a clamping diode is stray spikes in the rest of the circuitry causing erratic behavoir...
DigiTan said:How does it get the name "clamping diode?" I've always wondered about that one. I guess it has something to do with the diode "clamping down" on the back-EMF and creating a short(er) circuit for the surge?
ljcox said:DigiTan said:How does it get the name "clamping diode?" I've always wondered about that one. I guess it has something to do with the diode "clamping down" on the back-EMF and creating a short(er) circuit for the surge?
The term "damping" comes from damped oscillations. If you stimulate a RLC circuit into oscillation, the amplitude decreases with time due to the energy lost as heat in the resistor.
There are mechanical equivalents. For example - suspend a spring from a beam with a weight attached at the other end. If you pull the weight down and let it go it oscillates up and down. But since energy is lost in the spring and due to air resistance, the system gradually looses energy so the amplitude of the oscillation gradually decreases. It is therefore damped.
Len
k7elp60 said:Russlk is correct, but I would like to add that when the field collapses the polarity of the voltage is opposite, that is why the diode is installed the reverse polarity of the energizing voltage.
ljcox said:...When the circuit is opened, the inductance of the relay coil wants to keep the same current flowing (like Newton's first law of motion - a moving body wants to keep moving). So it generates an EMF in order to achieve this aim...