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  1. duke37

    12 & 24 Volt

    You will need at least four controllers, for side lights, brake lights and direction indicators. I would not recommend a resistor since if one bulb fails, the other bulbs will be overvoltaged and will soon fail. The controllers will either be complicated or dissipate a lot of power giving out...
  2. duke37

    Fence Charger Problem

    Last night I had a look at an Electric Shepherd fencer, the output transformer was open circuit. Fencers can be supplied from batteries or the mains, which is yours? It looks as if there is a transformer tacked away in the dark recesses, is this a mains transformer or an invertor transformer...
  3. duke37

    Sequence 10 leds on power up

    I have taken this information from the national.com site. P8 To ground to get bar graph. R2 Sets the led current. R1 Included to ensure that the tenth led lights. R3, C1 is the input voltage, this combination gives a time constant of about 10sec. Show us your diagram.
  4. duke37

    muffin fan at lower than rated voltage?

    Muffin "light flat round spongy cake eaten toasted and buttered". Yumm. If it is a shaded pole motor it should be all right, these are often controlled by input voltage (series resistance).
  5. duke37

    ITT310 substitute

    In the old days (I don't remember them well), power diodes were sometimes used in this application. You could try a 1N4007 if you don't have a modern varactor.
  6. duke37

    Need help in designing switching/chopping circuit

    An interesting problem! To get an idea of what is required, it would be necessary to know the inductance of the coil you wish to drive. Why does the transformer radiate a lot of heat and wear out? If it passes the same current when driven by solid state devices then it will get just as hot...
  7. duke37

    Need to create a 5V clock signal

    The cmos 4047 can give an approximate 1 pulse/sec with an accurate 50% duty cycle. It does this by running at double frequency and dividing by two. It all depends on what you want.
  8. duke37

    Capacitor and oscilloscope puzzle

    The smaller amplitude with the smaller capacitors is because you have a significant capacity in the probe, If the series capacitor has the same capacity as the probe then the voltage will be reduced by half. With the large capacitor, the load of the probe will be relatively little.
  9. duke37

    Capacitor and oscilloscope puzzle

    You have not included a reference (gound) line in your diagram, you cannot measure a voltage with only one wire. I presume you mean 5 kHz not 5 Khz. (K is degrees Kelvin, Herr Hertz would doubless like his name spelt with a capital letter) The series capacitor passes the high frequency part of...
  10. duke37

    Help with Alternating 12 volt DC Headlight flasher "WIGWAG"

    A 4047 CMOS chip will give two outputs in antiphase and will drive two mosfets directly. This will make a much simpler circuit.
  11. duke37

    timer motor circuit

    Yes, that looks right.
  12. duke37

    timer motor circuit

    Yes, the battery may have quite a high internal resistance. Try a big (say 1000 microF) capacitor across the battery. You could also put a 0.1 microF (100nF) across the motor.
  13. duke37

    Sequence 10 leds on power up

    Show us a diagram of your circuit. It should have a resistor from the supply to feed the input and a capacitor from input to gound to slow the voltage rise. Then the 'thermometer' display will gradually grow. The time constant of the input circuit will be R*C so 1 Mohm and 10 microF will give a...
  14. duke37

    timer motor circuit

    I have looked at the circuit and it looks all right to me. You could try disconnecting the motor in case the battery can not provide the necessary power and monitor the 555 output (pin 3). I do not see where the high frequency oscillation comes from but a big, fat electrolytic across the supply...
  15. duke37

    Portable Electric Grill Shorting?

    1. Try reversing the power connections, they are Lucar connectors and you have plenty of wire to swap them over. This is somewhat of a forlone hope. 2. Heat it up as before for a longer time. 3. Get a new element.or take it to the tip. I think you are on a loser here.
  16. duke37

    Transducer and transistor speed

    I would suggest that you use a phototransistor instead of the LDR because of speed limitations. It will need a suitable load resistor selected. A microphone could be use in a similar circuit but its output would be low so the reference point of the microphone should be close but not identical...
  17. duke37

    Got a question about driving LEDs? (Another work in progress)

    Hi Steve Great exposition! What is the purpose of the capacitors in output of the switch mode current source? What happens if there is no load, do the capacitors go pop?
  18. duke37

    Transducer and transistor speed

    You could use a charging capacitor, fed by a constant current supply, started when light is received, through a switch (cmos 4066) the charge would be stopped when the sound is received. The voltage on the capacitor would give the delay and could be displayed using a LM3914 and a bargraph...
  19. duke37

    Transducer and transistor speed

    You will know that Albert said that the speed of light is constant at 300,000,000m/s so your experiment is essentially measuring the speed of sound. LDRs are slooow and some phototransistors and photodiodes are quite fast. Your light generator will also need to be fast. Any standard...
  20. duke37

    Traffic Lights

    Here is a proposed circuit, is this what you want and what is your timescale? The bits will fit inside the Absaar charger even though I have added some heat sink to keep a replacement rectifier cooler. What cable and connectors are you proposing?
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