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Economy radar detector

This circuit uses a 1458 dual op-amp to form a radar detector. C1 is the detector of the radar signal. The first op-amp forms a current-to-voltage converter and the second op-amp buffers the output to drive the piezo transducer. R5 sets the switching threshold of the second op-amp; normally it is adjusted so that the circuit barely triggers on background noise, then it's backed off a bit. The response of the circuit may be tuned by adjusting the length of the leads on C1. For typical road-radar systems, the input capacitor's leads should be about 0.5 to 0.6 inches long.



By "Radio-Electronics" Magazine, Jul,86 issue (C) Copyright Gernsba

11 Responses to "Economy radar detector"

  1. metallica_boySeptember 13, 2008 at 5:20 PM

    has any one try this circuit email me plz mogey336@hotmail.com plz plz :D

    ReplyDelete
  2. Peyton McNullyDecember 18, 2008 at 1:05 PM

    at first glance i think C3 is showing the wrong polarity. The symbol should be reversed I think.

    ReplyDelete
  3. Jochtorius MangkasaFebruary 14, 2009 at 2:24 AM

    Thanks Mac. C3 in correct position.

    ReplyDelete
  4. AnonymousFebruary 19, 2009 at 12:54 AM

    This circuit uses a 1458 dual op-amp to form a radar detector. C1 is the detector of the radar signal. The first op-amp forms a current-to-voltage converter and the second op-amp buffers the output to drive the piezo transducer. R5 sets the switching threshold of the second op-amp; normally it is adjusted so that the circuit barely triggers on background noise, then it's backed off a bit. The response of the circuit may be tuned by adjusting the length of the leads on C1. For typical road-radar systems, the input capacitor's leads should be about 0.5 to 0.6 inches long.

    ReplyDelete
  5. AnonymousAugust 7, 2009 at 10:20 AM

    WHAT TYPE OF CAP. IS C1 AND C2?

    ReplyDelete
  6. AnonymousSeptember 5, 2009 at 7:37 AM

    ELECTROLITIC

    ReplyDelete
  7. ram.February 3, 2010 at 11:04 AM

    can I use any other op-amps like LM 324 instead of 1458 ??

    ReplyDelete
  8. AnonymousSeptember 12, 2018 at 9:58 AM

    This is not the radio electronics version I made years ago. It had a twin T oscillator instead of a piezo alarm

    ReplyDelete
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  10. sofiaAugust 10, 2026 at 7:03 AM

    Good overview of the main categories. IGET

    ReplyDelete
  11. saniyaSeptember 2, 2026 at 11:29 AM

    Helpful explanation of the main features. Iget refills

    ReplyDelete

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