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  1. I

    amping with a step down transformer

    To make it louder, switch the mains input of the transformer from "240V" to "115V", then run it on 240V. Guaranteed to make a loud bang, at least!
  2. I

    Ethics of buying electronic modules from Chinese sites?

    Low voltage DC operated gear is OK from China, but I don't trust mains powered equipment that is purchased directly from there. Most countries require an approval before the imported gear is sold in that country, hopefully they have torn down and inspected the samples supplied by the importer...
  3. I

    How to test this 24v 13" Worx Mower

    The "trigger" is more likely a "dead man's switch". I rescued a similar mower and that switch was O/C, so I just bypassed it. If you use your external supply to fire it up, it should be at least able to handle 3 or4 amps.
  4. I

    want to charge 2 18650 batteries as a 6v battery with a BMS

    You can buy a cheap 2,3, 4 or whatever number cells you want BMS online. Connect up a power supply to the input, connect the cells together and then to the BMS, then the load can be connected. I have converted just about every portable appliance I can to use 18650's, some charged by USB, some...
  5. I

    Switch question

    The first one is a standard contact type thermostat, with a series over-temp klixon. These thermostats are usually limited to around 65C. The overtemp may go at 70-75C, as fitted to standard electric water heaters. As said above, you need a minimum of a PTR on the outlet (pressure/temperature...
  6. I

    Make something move up and down with a push of a button

    If you are not worried about the speed it operates at, you could use a spring loaded 12volt automotive solenoid, like the type that operates trunk (boot) mechanisms. It will be nearly instantaneous.
  7. I

    Timed Relay query

    Reversing in tumble dryers is done through 2 sets of windings- one CW, one CCW. The supply to the windings is switched electronically. Easier to just buy a reversing tumble dryer.
  8. I

    Adding an audio output to an old answering machine

    Put a 1k resistor across the speaker output, and use this as your audio input.
  9. I

    Alternative to a bad tachometer filter?

    You could use a suppressor (capacitor) that you find on the back of an alternator or mounted on the coil.
  10. I

    Analogue Meters for Nostalgia Sake

    One place where a digital meter doesn't work too well is taking voltage measurements on a running Kettering ignition system, the display jumps around like a cat on hot tin roof. Out comes the AVO when I'm working on an old car. I used to work in aviation electrical about 40 years ago, all we...
  11. I

    Crock pot modification

    It is likely that the element is 220VAC, and the existing controller senses the temperature and just cycles the element on & off. You could substitute the controller you have pictured, just place the temperature sensor in the same spot as the original. Have a close look at the element and see...
  12. I

    Chinese diesel heaters

    If they use the "Facet" type fuel pump (looks like a transformer with an in and out fitting), you can quiet them down a bit by mounting them on resilient mounts. I have fitted several to cars this way, and it is hardly noticeable.
  13. I

    Heat gun motor pcb ?

    If it has the heating element in series with the motor/ rectifier, they sometimes have a thermal fuse in there, mounted in or near the element. This cuts power to everything if it blows. Looks like a little silver bullet.
  14. I

    With a Little Help from my friends?

    Many years ago I built a theremin using the circuit from an Australian Silicon Chip magazine, It used a telescopic radio antenna and had an audio amp with outputs for your "proper" amp.
  15. I

    DIY load for generator testing.

    We had one similar to use as a load on a genset, with a crank handle operated centre electrode so it could be raised or lowered to vary the load.
  16. I

    Soldering joint on thick 12v 30A wire

    As long as it is a good (not dry) solder joint, all should be good. Just make sure you have a good insulator (heat shrink, etc,) around the joint. If you don't solder well, practice on some scraps, you don't want the solder wicking up the wire under the insulation.
  17. I

    Help understanding this car seat heater diagram

    Because you have presented it with an extremely low resistance which it interprets as a very high temp. Put a 10k or 8.2k resistor in there instead, the unit should keep supplying power to the heater.
  18. I

    Help understanding this car seat heater diagram

    Thermistors can give different resistances to each other. They are usually identified as "X Ohms at Y degrees C". They are also available as NTC -Negative temp co-efficient-(as yours is) and PTC Positive temp co-efficient. Car manufacturers never want to spend more than they have to, so both...
  19. I

    Help understanding this car seat heater diagram

    The dotted line means that it is sensing the temperature of that part of the circuit, i.e. it is probably attached to that particular heating element. If you short "TH" and "SW" the heater should work. Just check that with power applied through the fuse that you have something (probably 12v) at...
  20. I

    Help understanding this car seat heater diagram

    The component would be a thermistor (thermal resistor), to provide temperature feedback to the controller.
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