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  1. Alec_t

    IR2153D

    From P2 of the datasheet: "Note 1: This IC contains a zener clamp structure between the chip V CC and COM which has a nominal breakdown voltage of 15.6V. Please note that this supply pin should not be driven by a DC, low impedance power source greater than the V CLAMP specified in the Electrical...
  2. Alec_t

    Lubricate Open-Reel Magnetic Tape?

    Have you meticulously cleaned all the tape guides? A build-up of oxide dust there can cause tape drag, so perhaps squealing?
  3. Alec_t

    Help needed with Weather Station

    Welcome to EP! Awaiting the pic. It needs to be close up, well lit and sharply focussed.
  4. Alec_t

    How would a twisted pair effect a signal

    For AC/radio-frequency circuits a twisted pair can be advantageous as it enables cancellation/reduction of some undesirable effects. However, there is no such advantage when, if I understand you correctly, the two wires of the twisted pair are in parallel. The additional resistance presented by...
  5. Alec_t

    Locating hidden 24v dc Relays.

    A pocket compass might work. The needle would swing when the relay coil is energised/de-energised.
  6. Alec_t

    Mosfet not Switching the current to load

    Welcome to EP! 1) What is the exact type number of your 555? Unless you are using the CMOS variety the 555 output voltage will be about 1.2V below the supply voltage, i.e. will be only about 1.8V. 2) A standard MOSFET needs a gate voltage (Vgs) of about 10V to turn on fully, so with only 1.8V it...
  7. Alec_t

    HELP with Schematics for magnet launcher

    If it's the same circuit you were considering over at AAC, it's potentially lethal nature has already been pointed out! It would likely infringe the Terms and Conditions of this site.
  8. Alec_t

    DC Motor Speed

    Connect a low-value resistor in series with the motor as a current sensor and check the voltage across the resistor with a scope. If it has a periodic component, that will be related to the rpm.
  9. Alec_t

    Phone call causes LOUD screeching noise from unknown location near my apartment building

    Just a guess, but perhaps there's some anti-tamper alarm associated with the meters and your phone (or something else coincidentally) triggered it.
  10. Alec_t

    Fuel pump /auto choke relay

    If you fried the coil driver (the ECCS control module) I doubt it's fixable :( .
  11. Alec_t

    Fuel pump /auto choke relay

    Hopefully you didn't bridge the relay coil terminals. That would likely have fried whatever drives the coil.
  12. Alec_t

    three phase rectifier voltage issue

    Are you sure the polarities of all the rectifier diodes are correct?
  13. Alec_t

    Could a water flow sensor sense gas flow?

    Be wary if the gas is flammable. The rotor seals may be liquid-tight but not gas-tight.
  14. Alec_t

    DC 9v replacement

    At least you have a polarity marking on the plastic. The centre pin of the barrel connector is +ve.
  15. Alec_t

    How is a brass gear removed from a DC motor?

    Haven't you got the gear off the shaft yet? We need to know!! ;).
  16. Alec_t

    how to determine the right voltage for led lamp?

    Conclusion: you'll need a ~300mA constant-current ~60VDC supply.
  17. Alec_t

    how to determine the right voltage for led lamp?

    I think you'll find that the light-coloured line is an insulating strip, not a power rail, and the darker areas are conducting paths connecting the groups in series. Can you confirm with a meter?
  18. Alec_t

    Control alternator voltage back to 6vlt battery?

    I'm not a bike guy, but it's my understanding that voltage stabilisation on older bikes with magnetos is usually achieved very crudely with simple shunt regulators. Such a regulator may be no more than a beefy zener diode or two to clamp the voltage to around 7V (for a 6V system).
  19. Alec_t

    how to determine the right voltage for led lamp?

    You mean they all share the negative line? That still leaves the puzzle.
  20. Alec_t

    how to determine the right voltage for led lamp?

    See posts 10 and 12. If 66mA is the maximum rated current, it is always advisable to run things at less than maximum to prolong their life, so 60mA per LED seems reasonable. I'm still puzzled by your assertion that "they all share the positive line but the negative is every 5 leds". If 18...
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