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Circuits designed by David Johnson, P.E.
Last Updated on:
Thursday, March 22, 2012 07:51 AM
Master Category List
- Dave's Circuits
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Receiver Circuits |
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175kHz Inductive Pulse Receiver
This circuit is discussed in more detain in the Experimenters Journal. The
receiver’s six inch diameter coil detects the ring signal from the above
transmitter and use a single NPN transistor to provided enough amplification
for the signal to be easily viewed on an oscilloscope
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2uS Light Pulse Receiver
Although the LF357 is an obsolete part, this
circuit gives you an idea how to build a sensitive modulated light detector with
high ambient light immunity. The first section uses a 100mH inductor as an
efficient photodiode current to voltage conversion circuit. The second circuit
performs much the same function but boosts the voltage generated by the first
circuit by a factor of X20 and filters out lower frequencies. Overall, the
conversion factor is about one volt per microwatt of light. Daylight noise is
typically less than 30mv peak to peak. The frequency response peaks at about
250KHz. Although I have not tested it, I think the Texas Instruments TLC081
should work in this application.
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