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  1. duke37

    Inverter Modifications

    If it is a ferrite cored transformer, it will never be able to run at 50Hz. To get 50Hz you will need an iron cored tranformer and the SG362 modifying to generate the correct drive. frequency. This circuit produces square waves. The output can be filtered to give an approximate sine wave or a...
  2. duke37

    help please about equivalent transistor

    Welcome hubi The transitors seem to be very similar and many other transistors are available. npn 65V 100mA Hfe >110. 100 or 150MHz They are both e, b, c. I have not checked if these are the same way round. I doubt if a faulty transistor could damage the amplifier but this will depend on the...
  3. duke37

    PIR operated DC motor project odd behaviour help

    What is the motor driving? Why do you need to regulate its voltage? A 12V motor running on 6V will run at about half speed. A 12V motor should manage 18V without damage if in a normal temperature environment.
  4. duke37

    PIR operated DC motor project odd behaviour help

    The NTLJD2105L is a p-channel mosfet and rated for only 4.3A. A IRF540 is much more rugged (N channel) IRF3205 (N channel) will take 110A Whether you need a p channel or n channel depends on your circuit. Just make sure that there is enough gate voltage to turn the fet on fully.
  5. duke37

    Soldering iron trouble.

    One technique which I have used on capacitors is to wind a lead around a jeweller's screwdriver. The other wire is passed through the helix and soldered. You could make a helix from thin wire and pass both thick wires through it. Remember to put some heat shrink sleeving on the wire before...
  6. duke37

    Anyone ever build a DC to AC inverter ? Needs to run on 32v DC

    What will the 120V output be used for? What frequency is wanted? Will a square wave do? You will need some high voltage transitors. I would go for an oscillator to set the frequency and FETs for efficiency. The transformer should run unsaturated.
  7. duke37

    PIR operated DC motor project odd behaviour help

    The old motors I have seen use one motor lead connected to the body, this may be at 12V depending on the circuit. There are two other wires, one for normal speed and the other for fast speed. If you have a 6V relay and want to supply it with 8V, then you need to drop 2V. A 6V relay on 6V drops...
  8. duke37

    PIR operated DC motor project odd behaviour help

    C2 100m? There are plenty of 6V relays around. You could add a small resistor in series to drop the 8V to 6V if required. There are plenty of 10A diodes around. I doubt if the motor uses more than this and a diode can take more than its rated current for a very short time. A fet would make a...
  9. duke37

    Copper Clad Aluminum vs Oxygen Free Copper use, trade off, voltage drop in DC circuits.

    A thin piece of flexible cable will be adequate to get the voltage across the fat cable.
  10. duke37

    TL 494 buck converter

    Without seeing the schematic it is impossible to guess where the DC comes from.
  11. duke37

    Old silent chap

    The most important voltages are T10 to T15, start with T12 and T15. Try the + lead of C417. All voltages relative to battery negative.
  12. duke37

    PIR operated DC motor project odd behaviour help

    I would think that a wiper motor could take much more than 1A, measure the free load current. The running current all depends on the torque required. The motor will behave as almost a short when turned on. What is the reason for a regulated supply when you are happy with either 12V or 15V.? If...
  13. duke37

    Panisonic folt f61

    It looks as if you can get a manual for a Panasonic receiver but you may have to pay for it. Others have had fault 61.
  14. duke37

    Can I re-use old components?

    I have repaired old valve radios 50 or more years old. Many of the components are OK. High voltage electrolytic capacitors will need reforming before use. Their working life is temperature dependent and modern ones are labelled with a maximum temperature. if run at a lower temperature, do not...
  15. duke37

    Need the Datasheet or specifications of NIC0K1L( ultrasonic transmitter receiver module.)

    I do not know how the sound can measure the velocity. When my kidneys were investigated using ultrasonic sound, the transducer was coupled to my torso with fluid. Sonar devices are immersed in the fluid. Any change in density will reflect the signal, I do not think you will get a significnt...
  16. duke37

    Amplifier burned, please help to ID parts

    What is the black grot on the transformer. If it is some pitch droped on the winding, then OK. Of it is a due to a shorted turn, then you will need a new transformer. Disconnect the transformer output connections and check for power.
  17. duke37

    Old silent chap

    If there is distortion, then the audio stage is wrong. You seem to be working in the right place. I assume you got the replacement capacitors the right way round. Measure the current draw of the set and measure the voltages in the audio stages. The symptoms would suggest a transistor gone leaky...
  18. duke37

    12v heating element dimmer

    In a bathroom there are strict regulations about the wiring. As far as I am aware, the only device which is legal is a shaver socket which has an isolating transformer. Lights must be switched with a cord. Others will know the regulations better than me.
  19. duke37

    12v heating element dimmer

    Please give details of what you have and how they are connected. Pictures are very useful. 12V at 3A is very small for a heater. 230V at 3A is very large so not likely to be what you have. Phase angle dimmers can have problems feeding transformers.
  20. duke37

    5KHz Regulated Supply

    What is a signal coil? Are you talking about a relay to drive a rail traffic light? Coils have inductance, give us details.
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