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Circuits designed by David Johnson, P.E.
Last Updated on:
Thursday, March 22, 2012 05:43 AM
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- Dave's Circuits
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Copyright © David A. Johnson, PE - ALL Rights Reserved.
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Train
Model Circuits |
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HO Train
Model Lighthouse Flasher
HO train sets often have authentic looking scale model homes and buildings.
The hobby circuit below can be mounted inside a model lighthouse. The
electronic circuit drives a single LED lamp in such a way that it produces
light which simulates the rotating light from a lighthouse beacon. It
uses a dual low power op amp IC.
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Miniature Lighthouse Light Simulator - The circuit I came up with is
shown below. It uses two dual low power op amps. The first two devices
form a classic oscillator circuit whose output is a triangle waveform signal.
That signal is routed to a current regulator circuit, which converts the
triangle voltage signal to a triangle current signal through the lighthouse
LED. A third op amp generates pulses timed so they occur at the peak of the
triangle waveform. The result is a LED, which gradually grows brighter,
then flashes even brighter before dimming again. This should produce a
light, which simulates a rotating lighthouse light...
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Visible Light Blocking Filter - This isn’t an electronic circuit but the
drawing below shows the curve for an optical filter made from exposed color film. The
material blocks most visible light but is very transparent to 880nM infrared light.
Kodak 100ASA is exposed to "cool white" fluorescent light for about 5 seconds.….
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