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  1. duke37

    Help with voltage regulator for 28V DC starter-generator

    There is a CAV regulator on UK e-bay for £30 and the firm autoelectric007 say they manufacture dynamos and alternators and will answer any questions.
  2. duke37

    Help with voltage regulator for 28V DC starter-generator

    Alternators are similar to DC generators (dynamos) except that they use diodes to rectify the AC instead of a commutator to do the same job and they are inside out. The current needed will depend on the resistance of the field winding. This may be difficult to measure with a digital meter...
  3. duke37

    Please help with replacing electromagnetic buzzer

    I think not, 3.6V will be the range of the voltage, peak to peak. The diagram in #6 may work but will put DC through the supply. This may or may not cause problems. I suggested a bridge rectifier which will not put DC through the supply but has an extra diode voltage drop which also may cause...
  4. duke37

    Help with voltage regulator for 28V DC starter-generator

    The regulator is of the old style with special relays to set the voltage. These often overcharged the batteries so shortening their life. Modern regulators use more accurate voltage generation. Cars use 12V but some larger vehicles use 24V and regulators should be available. You will need to...
  5. duke37

    Please help with replacing electromagnetic buzzer

    The first buzzer looks like a speaker, it takes AC since the voltage is specified p/p. The second runs on DC, try this on a 3V battery (two 1.5V cells). You may be able to use the DC buzzer if you run the AC supply through a bridge rectifier and smooth with a capacitor but the voltage may be...
  6. duke37

    12VDC to 100DC is it possible?

    An alternator is not needed. The motor can be used to drive the vehicle and can be used to brake the vehicle, you just need to make a complex control system. I do not think that you will get enough recovered energy to make regeneration worthwhile, just drive more responsibly. Railway...
  7. duke37

    12VDC to 100DC is it possible?

    If you use a push/pull invertor running 20A input through a pair of MOSFETs, then you will charge at about 250W so 3A and a bit out. Power above this is beyond my knowledge. What is the current output of your alternator?
  8. duke37

    Narrowboat (Waste) Holding Tanks - LED level indicator

    You could use a CMOS 4093. The power will be negligible only the led currents at about 5mA will be significant. I apologise for the poor quality of the diagram. Some filtration of the 12V may be necessary.
  9. duke37

    5v in 48v out

    You could use a standard op-amp to drive a transistor (FET?) follower running from a 60V supply. Attenuated feedback to the op-amp would set the output voltage. An alternative would be to use an audio amplifier which can be used in a DC feedback circuit. I do not know the numbers. You will...
  10. duke37

    SCR Rectifier Need cross Reference help

    It is possibly a simple phase angle controller. Can you draw the schematic? Try it controlling a bulb.
  11. duke37

    Maplin or CPC?

    It depends on what you want and where you are. CPC is part of Farnell and can supply almost everything. Maplin has local shops and you can check stock before you go there. I use both. You should also consider RS and Cricklewood Electronics. The trouble with CPC is that they bombard you with...
  12. duke37

    bee venom extract device

    I am not able to get at my information at the moment but one gate of a CMOS 4093 can make an oscillator with a resistor from output to input and a capacitor from input to earth. Varying the resistor will vary the frequency. There is a plethora of audio amplifiers which can run on 12V, using one...
  13. duke37

    bee venom extract device

    If the AC can be the same frequency as the mains supply, then a transformer run on the mains will do. Get one with multiple voltage outputs to suit your situation. If you need a different frequency, then you will need to make a suitable oscillator which can run off 12V DC.
  14. duke37

    Audio Amplifier distortion issue

    Seems a strange circuit,where did it come from? Measure the voltages with no input. Check that the speaker does not have significant DC across it.
  15. duke37

    PIR light circuit

    The LDR should not be in series with the LEDs, this should be replaced by a current control resistor. A base resistor should be added to control the base current. More information on the panel and LED assembly would help.
  16. duke37

    Can a 6v light bulb blow a 12v transformer

    A bit strong! Wire vibration in transformers can rub off the insulation and create a short. Also bulb filaments can fail from vibration, external or internally generated.
  17. duke37

    Can a 6v light bulb blow a 12v transformer

    Or the bulb was not fitted properly and the transformer was shorted. I blew a fuse on my car when I tried to change a bulb with the power on.
  18. duke37

    12VDC to 110VAC inverter needed

    I do not like the look of that circuit. The emitter/base junctions will be overvoltaged at 12V input. The frequency will not be stable, you would be better off driving the output devices from a separate oscillator. FETs are preferred these days because of the lower loss. This circuit will give...
  19. duke37

    AC/DC Power Convert Questions

    A 1N4007 is rated at 1000V and 1A and will do what you want and will be suitable for many other applications. The diode only has to pass the solenoid current for a very short time so can be overloaded somewhat. Adding a diode will slow the solenoid release and a series resistor may be desirable...
  20. duke37

    Converting a remote control from Battery power to DC

    You can get 12V battery chargers which can be set to output between 13.8V and 14.4V to float charge the battery. I presume that the battery has a capacity of 23Ah and can supply more than 23A for a short time and quite capable of starting a fire if you short it. Please post a sketch of the...
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