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  1. duke37

    3 phase generator

    D1, D3 and D5 are labelled wrongly.
  2. duke37

    Type of wires

    Make a coil and measure its resonant frequency with a known capacitor and a grid dip meter. Use the cable instead of the capacitor to calculate the capacitance. The cable length must be considerably shorter than the wavelength of the frequency in use.
  3. duke37

    Heating a steel strip with current? 'hot knife'

    The trouble with thin wire is that it will not have the strength to hold a loop. A thin wire can be used with a bow to provide tension even as it heats but this restricts to a straight cut. Almost any wire can be used, although an alloyed wire, Constatan, Nichrome, Kanthal, stainless, suture...
  4. duke37

    Overheat of electronic items

    Immerse in an oil bath.
  5. duke37

    Heating a steel strip with current? 'hot knife'

    AC and DC are equivalent for this application. I suggest something with a smaller area would be more suitable such as galvanised fencing wire. You will need a lot of current and some means of controlling it. I used a lamp dimmer feeding a transformer for my neighbours hot wire bow. Pulse width...
  6. duke37

    Confusing results from voltage amplifier circuit

    You seem to have both R1 and R2 connected to ground, this is wrong. I do not know where they should go without looking up the op-amp connections.
  7. duke37

    Limiting inrush current without power loss?

    A resistor, shorted by a relay or fet after a short time would do the job with very little voltage drop.
  8. duke37

    Inductance value problems

    What is a microwave transformer? I have one microwave cooker which can be moved easily and one which produces hernias. You could use a push-pull circuit using a LOPT transformer core or a pot core. Both of these can be wound with as many turns as required. Flyback inverters involve the...
  9. duke37

    Killing SSR (relays) - Need to understand

    There was a thread some time back on trouble with a kiln. The matter was not fully sorted but it appears that the bare heating elements were mounted in the ceramic insulation and considrable leakage occurred both when cold due to damp and when hot due to ceramic conductivity. Some investigation...
  10. duke37

    Transducer AC mv/V to 0-5 VDC Conversion........... I think?

    I had a look at the torque meter specs and see that it is a strain guage type. The signal conditioner will doubtless produce the excitation and also demodulates to DC. It needs quite some effort to read through the details of what you have.
  11. duke37

    Transducer AC mv/V to 0-5 VDC Conversion........... I think?

    Is the output of the transducer AC or DC? 1.5 mV/V? What is the Voltage? Is this the input AC voltage? Is 1.5mV what you get at full scale torque? Sounds like an LVDT type of transducer. It should be possible to amplify an AC signal and then use a precision rectifier to give a 0 to 5V dc...
  12. duke37

    Troubleshooting welder wire speed control

    I do not seem able to find if the TYN42 is a triac or SCR. Am I mistaken that the marking of the connections on the board differs from the picture shown at the side? Edit Sorry, it is an SCR
  13. duke37

    Design and wiring for a UHF antenna

    Go for a Yagi, the longer and the more elements, the bigger the gain. The antenna has no power gain, the gain specified is due to the restricted area sensitivity.A good design will have a large, narrow main lobe and very little sensitivity in minor lobes. The width of the lobe is related to the...
  14. duke37

    Tension/Pressure sensor?

    How about a spring balance? The problem with any system will be the jerks in the tension.
  15. duke37

    Relays - non latching or latching?

    It all depends on what signal you have, if it is active whenever the light is on, then a NO non-latching relay would be used. If you use LEDs, then they will probably take less current than a relay coil.
  16. duke37

    Relays - non latching or latching?

    But what is the current of each bulb? If no current is specified waht is the power?
  17. duke37

    Stabilising wienbridge sine wave using FET

    The CMOS 4060 is an oscillator/divider which divides by two several times. The minimum division is 16 so with a 4MHz crystal the output is 250kHz. Another divider of 5 will give 50kHz. It may be better to finish with a divide by two to get an equal on/off waveform.If the frequency is not...
  18. duke37

    Voltage regulator Comparison

    The chip outputs 2.1V, up to 6V input, not 2.1V input. A general purpose regulator such as a LM317T could be used with a couple of resistors.
  19. duke37

    Relays - non latching or latching?

    You could think about using a transistor instead of a relay, Smaller and cheaper.
  20. duke37

    Powering an old smoke detector

    I think the Manhatten Project used natural uranium metal fuel elements with graphite moderating blocks. This was certainly the case with the Magnox power reactors which I worked on in the 50s. The fuel elements were devilishly heavy, you did not want to drop one on your toe.:)
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