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 Eyeeye Robots Hints and Tips Solenoids

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Do relays and solenoids, operate slower with a back emf diode? Yes!

 Circuit click on it to get a better image

Eyeeye - Robots - Hints & Tips - Solenoids - Test Circuit

Eyeeye - Robots - Hints & Tips - Solenoids - The Setup
 The test set up.

The Circuit

On release of the switch the transistor powering the relay switches off, at the same time the second transistor starts the timer. The timer is then stopped when the normally closed contact of the relay relaxes into the closed position.

The tests

We did about fortyfive runs without, and about fortyfive with, the diode. The results are as follows:-




 No Diode

(Micro Seconds)

 With Diode

(Micro Seconds)

 Mean Duration  1676  16391
 Std. Dev.  2.2  17.6


The relay magnetic field collapse is slowed significantly by the diode.


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