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  1. kellys_eye

    Strain gauge purchase

    RS Components do some basic gauges ranging in price from $10-$20 - not particularly expensive and guaranteed to come with a data sheet. It should provide you with enough information to get started but I don't think sensors more complicated than the 'basic' versions will come 'cheap' no matter...
  2. kellys_eye

    Half-bridge driver for induction heating problem

    Yes, that's the basic layout...
  3. kellys_eye

    How to minimize acoustic mike<loudspeaker feedback?

    The shift (or delay) is measured in Hz and/or milliseconds and would be unnoticeable by most.
  4. kellys_eye

    RF Circuit Battery Efficiency

    You can still do that with MOSFETS - look up the 'h-bridge'.
  5. kellys_eye

    Ignition coil driver.

    You won't be putting 'amps' into the ignition coil - the ZVS output is very high voltage but relatively (if still lethal) current. It's the voltage that will cause the 'flash-over' and ruin the ignition coil. Also you probably can't measure the output of that ZVS, certainly using 'normal'...
  6. kellys_eye

    nuisance interference

    It may probably take more than one method to cure the fault. But screening that cable is a good place to start.
  7. kellys_eye

    Strain gauge purchase

    Personally I'd purchase a few cheap bathroom weigh scales and salvage the strain gauges (and electronics) from them. I have one set already (with older LED readout) that I originally intended to re-purpose to weigh propane tanks to indicate content. Another one of those 'when I get around to...
  8. kellys_eye

    nuisance interference

    Are the power cables to the devices particularly lengthy? Do they run in proximity or parallel to existing mains wiring? If the system is being false-triggered it can only be by 'fake' signals into the motion sensing device so check the wiring to/from it and the quality of the PSU/wiring...
  9. kellys_eye

    Distorted waveform on Triplett 3432-A sig gen

    ....and thank you for updating us on your successful solution. Nice job!
  10. kellys_eye

    Help with bridge rectifier

    OK, if 8/9 is only 3.5VAC you could still use it if you used a voltage multiplier stage for rectification to bring the output up to around 9V (so a three-stage multiplier would be required) which could then be applied to the 5V regulator. Another way would be to bridge-rectify the 3.5VAC (you'll...
  11. kellys_eye

    RF Circuit Battery Efficiency

    Why the L293? Can't you use simple MOSFET drivers for switching?
  12. kellys_eye

    Ignition coil driver.

    Any form of oscillator attached to the primary of a car ignition coil should produce an output on the high(er) voltage side. The voltage put 'out' will be proportional to the voltage put 'in' multiplied by the turns-ratio of the transformer (coil). You are only limited by the breakdown voltage...
  13. kellys_eye

    LCD Display (Basic)

    Good find <thumbs up> I expect such devices are not cheap - certainly when they don't publish the price openly (you have to ask!) you have to be cautious. Apart from the label itself, you'd have to purchase the programmer.
  14. kellys_eye

    Half-bridge driver for induction heating problem

    The MOSFET driver stage looks all wrong to me. The sources should be ground and the drains connected across the LC circuit and each drain connected to your supply line via choke (filters) of, say, 100μH. C10 not used/required.
  15. kellys_eye

    Ignition coil driver.

    No, you can't use it. The primary of a car ignition coil is meant for 12V only - sending the output of the ZVS into it will just cause flash-over in the winding and ruin it.
  16. kellys_eye

    Issues with arduino power from cars accessory power fuse

    Have you got a heatsink on the regulator? Sounds very much as if the device is shutting down after over-heat alarm (built-in protection).
  17. kellys_eye

    Advice before buying an Inverter

    Yup.
  18. kellys_eye

    Sencore LC53 leakage test acting up?

    Film capacitors should be fine - I should have clarified that I was referring to the electrolytic in the 'orange' case....
  19. kellys_eye

    Interfacing industrial signals to microcontroller ADC

    Considering even the best quality multimeters rely on resistor networks to attenuate - before passing it to the ADC - the statement that a voltage divider 'isn't accurate enough' is bollox. Get your teacher to explain why he thinks this is the case.
  20. kellys_eye

    Advice before buying an Inverter

    Nope. The 120W motor will draw 0.5A at 240V (0.5 x 240 = 120) and twenty times that at 12V - so 10A. This assumes 100% efficiency which you NEVER get so add 25% for leeway - call it 12.5A from the battery, minimum. If your battery is rated at 65Ahr (typical small car battery) then, in theory...
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