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Circuits designed by David Johnson, P.E.
Last Updated on:
Thursday, March 22, 2012 07:58 AM
Master Category List
- Dave's Circuits
Text & Graphics
Copyright © David A. Johnson, PE - ALL Rights Reserved.
LINKING to Dave's circuits is permitted but DO NOT COPY to your WEB SITE server! |
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Potentiometer Circuits |
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Pot
Controlled Variable LED Intensity Circuit
The circuit below uses power from four rechargeable AA NiMH cells to drive 3
white LEDs. A potentiometer varies the duty cycle of a pulse width
modulator circuit to vary the intensity of the LEDs from 0% to 100%. The
beauty of the circuit is that when the pot is all the way toward 0%, very
little power is drawn from the battery. Likewise, when the pot slider is
moved toward the 100% end, full power is fed to the LEDs. In effect, the
pot becomes the on/off switch.
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- Ten Turn Pot Forms
Frequency Readout
Let’s say you are designing a signal generator for a test fixture. To adjust the
frequency you would like to use a ten turn pot with a nice dial mechanism attached as a
frequency display. However, a display range of 0 to 9.99 would be impractical since
there is no such frequency as 0. But since many pot dials have a display....
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