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  1. C

    buy chipless rfid tags or something similar?

    Chipless tags work on different frequencies from different manufacturers. These are the tags put into books etc. Get them from book shops etc.
  2. C

    How to connect led light with mobile headphones

    The short lead of the LED goes to the ground wire and try the other wires with the music turned up loud.
  3. C

    Temperature control

    Simply put the thermistor in place of the pot and see what RPM you get at the temperatures you are talking about. Put the thermistor between the high-voltage end of the pot and the wiper. Put a 1k to 10k between the wiper and 0v. Let us know what RPM you get and we will work out the next step.
  4. C

    Magnet Alarm Circuit Board, Battery Power

    The circuit is an oscillator that produces 80v It will not drive a fan.
  5. C

    AC Diode

    You have to draw a much-more accurate diagram so we know how the feed is entering the pump and how the indicator light is connected.
  6. C

    Need help selecting a LED Driver

    Do you want to drive all of them in series at the same time?
  7. C

    Transistor switching on another voltage supply

    Add a transistor to drive an optocoupler and the other side of the optocoupler switches the 12v circuit.
  8. C

    Calculator fault: certain segments aren't showing on LCD

    The fault lies in the connector strip. You need to add extra pressure to get the connector to touch both the PC board and the strips on the LCD module.
  9. C

    Not getting the ideal 555 output

    The problem is this: Your resistor-fed power supply will deliver about 25mA and this is all being "eaten up" by the LED and other components. You have nothing left for the 555. Of course the circuit will not work.
  10. C

    Transistor Switch?

    That's the fault of your battery not the chip.
  11. C

    Transistor Switch?

    Connect the relay to pin 3 and it will work
  12. C

    LC Oscillator

    Such a range is beyond the capability of a beginner.
  13. C

    switch amperage for cordless drill

    When the motor stalls, the current will be much higher than 5 amps. It is normally 30 amps
  14. C

    12v rail vs 5v rail computer psu

    Add a 3R3 10watt resistor and let us know
  15. C

    Variable switch

    It's called a push-push switch. 30 cents on ebay.
  16. C

    FET and capacitor in series question

    It all depends on how much current your power supply can deliver.
  17. C

    More efficient LDR "dark" switch?

    Reduce the 1M to 100k
  18. C

    More efficient LDR "dark" switch?

    Change the pot to 1M
  19. C

    More efficient LDR "dark" switch?

    That's what it means.
  20. C

    More efficient LDR "dark" switch?

    1. Remove the LDR and see if the LEDs come ON. 2. Take the collector of the first transistor to 3v via a 1k.
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