Circuit Explanation

Discussion in 'Electronics Resources' started by Tithers, Dec 9, 2012.

  1. Tithers

    Thread Starter New Member

    Dec 1, 2012
    3
    0
    Hi

    I have a circuit that I picked up as a kit from Maplin. The circuit works by turning the LED on if there is no 38khz IR beam detected. If a 38khz IR beam is detected, the LED shuts off.

    I have a few questions about the layout of the design. I want to know if the R3, C7, R6, and R7 combination a filter circuit leading into the transistor?
    The IC3 is a IR receiver. I read somewhere that the 1N4006 is a high speed switching diode. Because the IR receiver is picking up a frequency of 38kHZ does that mean that the diode is allowing a logic zero current through?


    D2: 1N4006
    IC3: TSOP2438
    Q1: BC558
    Q2: BC548

    R2: 100R
    R3: 220K
    R4: 220K
    R5: 10K
    R6: 220K
    R7: 220K
    R8: 330R

    C6: 4U7
    C7: 100n
     
  2. Sensacell

    Well-Known Member

    Jun 19, 2012
    1,131
    267
    Looks like the diode is part of a simple RC glitch filter that serves to quickly discharge C7.

    The diode can be any switching diode, 1N4148 for example, the 1N4006 part is a high-voltage diode, not quite necessary for this circuit.
     
  3. Tithers

    Thread Starter New Member

    Dec 1, 2012
    3
    0
    Ok cool, do you know where I can find more information about it?
     
  4. Sensacell

    Well-Known Member

    Jun 19, 2012
    1,131
    267
    Can you be a bit more specific? Which "it" are we talking about?
     
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