PWM with 555 IC and Relay

402

06:46:53

Replace lamp for a DC Motor. 

published 11 years ago

sunx

11 years ago

Looks like 1V is not enough for relay, 5V works better. And could you explain me, what diode parallel to lamp is for? I always see it on such schemes but can not understand, what is it for :-(.

Mamish

11 years ago

The diode is for inductive loads like motors. A sudden disconnect when current is running through the inductor, i.e. every off cycle of the 555, causes a large reverse voltage spike (back emf) that could be damaging. The diode is reversed to pass that voltage safely with affecting normal current flow.

Mamish

11 years ago

(Correction: back emf usually refers to a different motor idea. Most people would call this flyback instead, hence "flyback diode".)

sunx

11 years ago

Thanks a lot :-)

Zucaritas

11 years ago

Sorry, I didnt change the Voltage, the diode is use to protect our motor (In this case, our lamp) of Overloads, greetings!:)

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