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Latching Relay Circuit Help

Discussion in 'Beginner Electronics' started by resrfglc, Dec 25, 2006.

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  1. resrfglc

    resrfglc Guest

    Years ago John had one of those cheap alarm switches for his van. It was
    supposed to work by making contact if the van was disturbed. It consisted of
    a springy piece of metal that would make contact if it was shaken.

    Problem was, it would only make a series of momentary contacts while
    whatever energy that was shaking his van continued and stop doing so as
    things quieted down.

    So I devised a circuit that would be triggered by the initial momentary
    contact and "latch" for X seconds providing the 12VDC to the Alarm Bell.

    Over the years I LOST the circuit diagram but kept the circuit. As I failed
    to label anything on it, I now have a circuit with six leads (One Red, One
    Black, two ORANGE and two WHITE with ORANGE strip(s).

    These attach to a small circuit board and two resistors [Red Red Green Gold
    1W(?), one capacitor [22mf 50v Electrolytic) and third device with three
    leads and a heat sink affair drilled for an 1/8" screw or bolt. It is
    labeled Motorola 827 and, above that appears "F 511" and above that what
    looks like an "I" and an "R" on either side of a stamped impression I cannot
    read. It is about 1/8" thick and 3/8" x 3/8" with the heat sink stuck on the
    back and extending 1/4"

    Looking at the black, three-lead device from the "front" I'll call the leads
    1, 2 & 3.

    I'll call the BLACK lead GROUND (-) and the RED lead 12V+ (good guess,
    probably correct - no?)

    That leaves two other "pairs of leads," ORANGE and WHITE/ORANGE.

    I assume one of these must be toe leads that when to the N/O Momentary
    contact switch (the alarm "sensor") and that the other two ran to the
    signaling device (12VDC bell).

    Which, he is asking you all, is which?

    Now, the Positive lead runs to a junction with: One of the ORANGE, one of
    the ORANGE WHITE leads simply tying all three together.

    The BLACK lead connects to PIN3 of the Motorola Device both resistors and
    the (-) end of the capacitor.

    PIN2 of the device is connected to the other ORANGE WHITE lead.

    PIN1 of the device connects the other ORANGE lead, the (+) end of the
    Capacitor and the other ends of the two resistors (probably could not get
    the resistor in the OHMS needed so ran two in parallel as a work around).

    As I recall, shorting across either the two ORANGE leads or the two ORANGE
    WHITE leads would send 12VDC down the ORANGE WHIITE or ORANGE leads (ringing
    the bell) for a period of time determined by the capacitor or resistors or

    If this circuit (or the Mororola device) is recognizable to you, please help
    me figure out 1) where to connect the trip NO MC Switch and load or (and) 2.
    where to find a schematic.
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