Search results

  1. C

    Reading PIC ports

    You can't bit-test. You must nibble-compare. Or you do a decrement and compare.
  2. C

    12v 3amp battery charger lead acid

    The 3A transformer is 2A DC. It's not the fault of the transformer. It's just that can only take 2 amps from the output of a bridge circuit that has a filter capacitor because the output voltage will be 40% higher than the voltage-rating of the transformer. This means we will be getting about...
  3. C

    12v 3amp battery charger lead acid

    The volts go up and the amp come down - the watts (VA) stay the same.
  4. C

    12v 3amp battery charger lead acid

    Just use the transformer, 4 diodes and a resistor. The 3A transformer is 2A DC
  5. C

    Design filtering capacitor

    Choosing a filter cap (electrolytic). The ripple is 5v per 1,000u. If the 3-terminal regulator requires an input voltage that is 6v less than the voltage on the electrolytic, you will never see any ripple. Use the same reasoning for higher currents.
  6. C

    Power supply + and -

    Don't forget the ripple will be 10v for 1 amp and the margin you have is less than 7v.
  7. C

    PIC Micro Output I/O

    No. The micro makes the output HIGH or LOW. The 10k has absolutely no effect what-so-ever.
  8. C

    how to discharge battery

    Here is what you need: It's and automatic tester : RECHARGEABLE BATTERY CAPACITY This simple circuit tests the capacity of a rechargeable cell. Connect a 4R7 (yellow-purple-gold-gold) resistor across the terminals of a clock mechanism and fit a fully charged rechargeable cell. Set the hands to...
  9. C

    Reading PIC ports

    The first thing you do is set up your output port with 8 LEDs on 8 x 330R resistors. Then create a sub-routine that clears the port then increments the port and calls a delay and loops. Watch the LEDs increment. Then put 4 x 10k on the lower nibble of the input port and take them to 0v...
  10. C

    Reading PIC ports

    You constantly loop around the following 8 sets of instructions: (2 are below) movlw xxxx 0001 subwf porta,1 btfss 03,2 goto $+2 the files match goto movlw xxxx 0010 subwf porta,1 btfss 03,2 goto $+2 the files match goto
  11. C

    Not getting oscillation as per circuit given

    By the time you put 22p in parallel with 22p and 330k you are going to have an RC oscillator below 32kHz.
  12. C

    Resistors

    As you get more advanced, you will know that the current will flow in the two resistors such that twice the current will flow in the 1k resistor. But it is much easier to have a big block of chocolate and cut it into 3 pieces. I get twice as much as you. This means you can work out in your...
  13. C

    Help with circuit (voltage doubler)

    Starting at the first half cycle. Nothing happens when the input goes positive. But when it goes negative, diode D2 flips over an the cathode goes below the lower rail and it prevents the right lead of C1 going any lower than minus 0.7v. The left lead of C1 goes lower than the bottom rail by...
  14. C

    Circuit failure indicator

    Simply wind a number of turns around a reed switch and add it to the line.
  15. C

    A few questions on electronics

    1. If the output of the mic is 2k2, and you deliver the signal into 2k2, the signal will be attenuated to 50%. That's why you try to make the "load" as high as possible. 2. Normally the coupling cap is 22n to 100n. 3. Only use 6 layer if you cannot get connections (tracks, traces) from one end...
  16. C

    Help in converting a wireless doorbell into a remote gate switch

    You really need a 5v CMOS relay between each project. Use the transistor to drive the relay.
  17. C

    Sound activated alarm

    There are blind dogs and deaf dogs. I have a blind dog. I have to lead him around very carefully so he doesn't bump into things.
  18. C

    Help me with LIN regulator Tester

    "I do not have much knowledge in electronics, " This is way beyond you.
  19. C

    Piezo To Detect Sound

    We use a piezo as a contact mic to hear right through glass with our wall bug transmitter. A bit tinny but as clear as a bell.
  20. C

    Transformer primary voltage exceed the rated voltage

    When you supply say 230v to a transformer, the magnetic flux produced by the current cuts all the turns of the primary and produces a back voltage of about 225v. In effect, the transformer is only seeing a voltage of 5v and when combined with the resistance of the primary (about 50 ohms) only a...
Top