When using large inductive devices like motors and solenoids, a flyback diode should be used. When voltage to inductive devices is removed, a large voltage spike can be created, which can cause issues with electronics (including lose of USB communication from GCU to a computer). The diode should be installed with the white bar lead on the positive side and the reverse attached to ground.
Comments (1)
Andrew Schofield said
at 9:59 am on Feb 23, 2012
Early digital telephones were prone to damage when electric arc welding was performed nearby the set. It seemed the telephone always rang when beginning welding.
Fiber optic signal-cable replaced one troublesome copper wire run to protect prisoner survellience equipment components damaged in every thunderstorm (Thor's hammer) since,
at a small northern Michigan prison.
A photo-isolator chip can alternatively be used in the load circuit for preventing potentially destructive flyback voltages while energizing/de-energizing:
mechanical relays, solenoids, or motors.
Here is a nice off the shelf protective device that can simply plug into an Arduino P3 pin header:
http://labjack.com/catalog/ps12dc
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