Search results

  1. B

    Radio detector + emitter

    There is a small doppler effect module to use with Arduino which works on microwave. Not exactly a plug and play device as it needs some work. You can check it out in the video here......
  2. B

    How do you install a power dimmer on a foam cutter tool?

    Ok, just be aware of the cost. The one I pointed to was around $48.00. If "portable" then the battery system alone will cost at least that much.
  3. B

    How do you install a power dimmer on a foam cutter tool?

    It's the output transistor or mosfet in a driver circuit. Because of the high currents involved, it is likely that it will need some form of heat transfer especially if not driven hard on. You do realise there are wood burning tools out there already..??? Might be difficult to find a portable...
  4. B

    How do you install a power dimmer on a foam cutter tool?

    No idea what a STEM project is, however, most foam cutters at least, run nichrome wire on 24v transformer with a standard light dimmer on the primary. Reason being the current requirements are much lower. My system here for cutting foam cores up to 1 metre long uses a 200va transformer with 2...
  5. B

    AC Laptop Adapter -> How to make 19v output into 5v?

    Forget the laptop p/s and use say a 350W atx supply. You should be able to get your 15A @ 5V fairly easily directly out of a standard unit. Just need a bridge on green to black to switch the unit on.(PG ....Power Good)
  6. B

    Sensing AC voltages

    Everyone learns something new everyday I imagine. https://www.jameco.com/shop/keyword=Hall-Effect-Voltage-Sensor
  7. B

    Are UJT's used anymore?

    Futurlec have 2n6028 https://www.futurlec.com/Transistors/2N6028.shtml Ebay.au have a china source of 2N1671A Motorola @ around $9.00 with post. https://www.ebay.com.au/itm/1PCS-2N1671A-CAN3-Transistor/273459456467?hash=item3fab7429d3:g:uRQAAOSwQwZacZMT
  8. B

    Silent electric motor to drive turntable.

    Worm drive gearbox would be relatively quiet with a crank output for the 90 degrees and the motor would continually turn in the one direction. Worm drive as an added plus are high gear ratio in small space. Could adapt a small cap run motor from the likes of a small twin tub washing machine...
  9. B

    Inline fusing 12v feed

    In addition to what you have, I'd be inclined to fuse each relay as each circuit exits each relay(87) with a fuse for that circuit. Having only the one line fuse at the source means it would have to be rated at the maximum of all circuits and would probably only blow when some dead short is...
  10. B

    Capacitor Substitution

    TO92 case device to the left of the MC34072P looks like it has the top chipped off it.
  11. B

    CAR LED headlight - load resistor (aka "CANBUS")

    Calculations do not make any sense. 8R to begin with is 1.5A whereas an original H7 lamp at 55W *2 = 110W = (roughly on 12V) 9.2A so if the ECU or whatever is monitoring the system, this resistor certainly would not fit the bill. Again 8R on 12V is 18W so do not seen why the 200W resistor. I...
  12. B

    Is it safe to replace B10 MCB with C10?

    The 6 and 10 are indeed the KA rating of the breaker. In many instances it is desirable to have a higher KA rating breaker installed. In Aus, 3KA breakers were the standard for many years but now it is 6KA. No idea what country you are from but in many with MEN system, double pole on the main...
  13. B

    restoring old garage door opener-receiver/transmitter

    If you are using a manual push button to operate the door at present, no need to go any further. Simply wire the two cables from there to the common and normally open contacts on a wireless relay with a momentary contact mode programmed as I showed you in post link # 2.
  14. B

    Sensing AC voltages

    Another method....
  15. B

    Sensing AC voltages

    I believe the sensor inside contactless volt sticks is hall effect.
  16. B

    Restoring ancient digital watch.

    When one has had enough experience one knows when one is beating a dead horse.
  17. B

    restoring old garage door opener-receiver/transmitter

    It was an EXAMPLE of what is available to suit your application. I'm not going to do all your running around for you, all you have to do is LOOK for yourself. Plenty of places LIKE Ebay and Amazon who have exactly the same units. Some will have just the remote but it will be of little use to...
  18. B

    AC Polarity swapping circuit

    I think it would be a great help to know just what the outcome of all this would be used for. Surely you mean out of phase.
  19. B

    Restoring ancient digital watch.

    Might be far better off going the Ebay route. As an example...... AU$10.00. https://www.ebay.com.au/itm/Working-Mens-1970s-Gold-Phasar-2000-Digital-Watch/274033107044?hash=item3fcda56064:g:1aAAAOSwEDFdko9S&frcectupt=true
  20. B

    Amp repair

    From the look of the visible tracks it looks like it been through a "corrosion bath". I'd say beating a dead horse trying to "repair" that lot.
Top