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  1. duke37

    ac to dc converter with speed control

    You had the same advice from brevor and jpanhalt. I also gave the same information in your duplicate thread. There is a minimum speed control, have you set this correctly?
  2. duke37

    I can't seem to figure out the component from this schematic

    There are sixteen heaters shown for sixteen tubes. V301 GZ34 shows the heater inside the tube under the cathode. This tube has a separate heater feed since the heater is at the high tension potential. Other tubes will have the heaters insulated from the cathodes with one side connected to...
  3. duke37

    New Moderator

    Congratulations Kris, I promise to behave.
  4. duke37

    LM317T Adjustable Voltage Regulator HELP ?

    The 317T needs about 2V across it (the droput voltage) in order to work so you will not get above 10V with 12V going in. If there is ripple on the input voltage, then it is the voltage trough which is critical. To get more output voltage you need more input voltage.
  5. duke37

    Car Battery Load Test Results (Is this good or bad?)

    9.6V at the battery seems reasonable to me. It could be much lower at the starter due to poor connections and wire resistance. Make sure that the engine is properly bonded to the chassis.
  6. duke37

    This should be simple for you guys...

    Motors come in many different types. Single phase AC Shaded pole. Capacitor start (needs a switch) Capacitor run Capacitor start and run (needs a switch) DC motors do not need capacitors except for interference suppression. You should try another capacitor, maybe not exactly the same...
  7. duke37

    LM317T Adjustable Voltage Regulator HELP ?

    Use 240 for R1 and 5k or 10k variable for R2. There should also be capacitors across input and output to ensure stability.
  8. duke37

    Car Battery Bounce Eliminator

    Use a sidelight bulb as the resistor then you can see what is going on.
  9. duke37

    Building a simple clock

    You could do the whole lot with circuitry but it would doubtless be better to use a PIC or similar. An input of 1 pulse per second would be easy and the computer could do further division and display driving It is 30 or 40 years since I used a 6502 so I may be out of date. Accuracy will not...
  10. duke37

    Building a simple clock

    The CMOS 4060 will make a crystal oscillator and 14 stage divider all in one. The oscillator will need to be trimmed with a variable capacitor if high accuracy is required.
  11. duke37

    [HELP] Op-Amp used in resistance detection circuit.

    There are lots of op-amps and I am not up to speed with them. A constant voltage supply holds the voltage constant regardless of the current draw. A constant current supply holds the current constant regardless of the voltage necessary. There is obviously a limit what can be done. An...
  12. duke37

    This should be simple for you guys...

    The metal box is a thermostat which switches the Lucar connectors. It is obviously not used and I cannot see any scratches on the connectors but then, I could not see 8. The capacitor should be tested by substitution since they can break down with high voltage. There is no point attacking it...
  13. duke37

    [HELP] Op-Amp used in resistance detection circuit.

    That looks quite good but R5 is not necessary. The output will not be linear since the current will depend on R4. This could be taken care of by calculation. An alternative method would be to use a constant current power supply of 40mA giving 0.4V with a 10 ohm resistor. Would this give...
  14. duke37

    This should be simple for you guys...

    The black block is a capacitor, probably run type. Failure of this will stop the motor. ?.0 µF, 450V AC at up to 70C there appears to be two extra connectors on this, were they connected?
  15. duke37

    Help Need gasoline injector pulse emulation for a Diesel engine

    I don't think I can help with the electronics, however, I wonder at the safety of welding to the flywheel. I would not like half of it to go for a flyabout. Do you crack test the welds?
  16. duke37

    RCD Fault - I'm dumbstruck

    I investigated a similar fault in my parents house. Everything normally worked all right but tripped the RCD on sunday morning. It turned out that there was a neutral/earth fault and this did not trip the RCD when the demand was low but when the demand was high, the drop along the neutral wire...
  17. duke37

    PSPICE rectified AC to voltage regulator

    I am a simple soul and I often get things wrong but not here I think. The negative feedback is only around the op-amp/Darlington, giving a gain of one. To get oscillation the loop gain has to be more than one, but in this case there is attenuation so oscillation does not occur. A much...
  18. duke37

    PSPICE rectified AC to voltage regulator

    An ideal op-amp doesn't need a supply ! The op-amp and Darlington have a gain of one, just a complcated emitter follower. Rh and Rl attenuates the output (X) to 0.916 *X. The input to the op-amp is the same as the output. X = 0.916 *X + 1.25 X (1 - 0.916) = 1.25 X = 1.25/0.084 = 14.9...
  19. duke37

    Help please!

    Will the LM3914 bargraph display chip do what you want?
  20. duke37

    New guy - need a block heater for Evinrude

    You do not say if the engine is fueled by petrol or diesel. If the compression is poor, a diesel will not start. If temperature is the problem, then it is the fuel which needs to be heated, this will be difficult with the very large bulk of the aluminium block The heaters you reference...
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