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  1. duke37

    What is this component

    Are you sure that the led is faulty? Get a 6V battery and place a 1k resistor in series and connect to the battery. Try both ways round. I have an analog meter which has 3V exitation for resistance measurement. This will often just light an led on the lowest resistance range
  2. duke37

    12V DC Motor (RS-550PC-8516) had some problem

    If there are sparks, then it is probably a brushed motor with the brushes rubbing on to the commutator. Sparks will occur when the contact is not good such as when the brushes are worn out. Worn brushes can be replaced They can also occur when the armature is damaged and there are large voltages...
  3. duke37

    Best way to get a replacement part for a switch?

    Please do not upset 73's de Edd, he is one of the most valued contributors here and can find stuff on the internet that no-one else can find, maybe even a specific little switch. He does need a starting point though. I see no sign of bullying. Please provide a good photograph and dimensions...
  4. duke37

    Attenuating a voltage signal

    How do you compare two AC signals? Do you want to compare the voltage at any instance? If so, the signals must be the same phase, alternatively they can be rectified and smoothed to give a comparison of DC voltages.
  5. duke37

    Can AC/DC be placed into a D Flip Flop?

    The CMOS 4013 D flip-flop changes state when the input changes from ground to positive. The question is whether you call this AC or varying DC. Make sure that the input stays within the power supply levels.
  6. duke37

    Need help with muscle stimulator project

    You could try a 12V mains transformer used the 'wrong way round'.
  7. duke37

    Need help with muscle stimulator project

    2300Hz is 2.3kHz or 2k3Hz. It is Hz not hz, Herr Hertz prefers a capital for his name. If it does not work well at lower frequencies then I would suspect that you do not have sufficient inductance. Xl = 2*pi*f*L
  8. duke37

    16 Volt DC conversion to 12 Volt AC

    I have not been able to get full details but there is a board based on the L298N chip. It can switch a pair of outputs 46V 2A each. These could be paralleled for 4A. The input requirements are not given properly but 0V or 5V will switch. The current is not clear, I presume the CMOS could drive it.
  9. duke37

    16 Volt DC conversion to 12 Volt AC

    The H bridge unit I have seen has a 5V output, this will be used for internal circuitry so not as simple as your circuit. The lower transitors are likely to be n-channel fets and the upper transistors will be p-channel fets, thus connecting the gates of the left fets together, then either the...
  10. duke37

    16 Volt DC conversion to 12 Volt AC

    There is no low side or high side. The three gates are spare and their inputs could be connected to ground to stop them going wild. Here they are used as a buffer to give them something to do so that they behave, the inversion is quite incidental and just shifts time by one hundredth of a...
  11. duke37

    16 Volt DC conversion to 12 Volt AC

    I will have another go.
  12. duke37

    Photo upload problem

    Dave Thank you, I will need to get some better eyes. Trevor
  13. duke37

    Photo upload problem

    Dave I have hand drawn a circuit and the laptop has taken a selfie to generate rather a grotty picture. This is 320x240, 225KB The problem comes when I wish to attach it to my thread reply, I see no way of doing this. Other programs show a paper clip to upload a picture. What am I not doing...
  14. duke37

    Photo upload problem

    I am wanting to upload a sketch but there does not seem to be a way of doing this. My memory is not good but did there not be a paper clip to attach a picture or is this only done in other programs. Others seem to be able to do it.
  15. duke37

    Charged or discharged

    There are many amusing ways of b******ing equipment.
  16. duke37

    Water as a conductor?

    Water is a very good insulator. It is used to cool radio valve anodes at several kV. Impure water with ionic salts will conduct, the resistance will depend on the water purity. To make your system more sensitive, then an amplifier will be needed. A single fet may be enough. Use a diode across...
  17. duke37

    16 Volt DC conversion to 12 Volt AC

    You only need one gate of a 4093 to make an oscillator. The frequency is 2.7/(R*C). You may want to use a variable for R if the frequency is critical. The three unused gates are given something to do to stop them causing havoc. I do not see a paper clip to attach a sketch.
  18. duke37

    16 Volt DC conversion to 12 Volt AC

    I would use a gate in a CMOS 4093 and a resistor and capacitor to make an oscillator. Feed the signal into a cheap H bridge, there is one which will output 5V suitable for driving the 4093. Total cost about £3. (GBP) A 555 is a little more complicated but would do. This would be well worth...
  19. duke37

    16 Volt DC conversion to 12 Volt AC

    12V AC is 34V peak to peak so a transformer or an H bridge will be required. A square wave is easier to generate and the motor may well run OK on this. A DC motor would be the easiest way to go.
  20. duke37

    16 Volt DC conversion to 12 Volt AC

    What do you wish to do with the AC generated? What frequency should the AC be? What waveform do you want? What power do you want?
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