| Electronics > Beginners |
| Standard electric kettle as a DC dummy load ? |
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| Nusa:
--- Quote from: max_torque on July 15, 2018, 10:33:45 am ---If you need to pull really high currents at low voltages, get yourself a roll of 1/4" (or 6mm for people who live in proper countries..... ;-) ) diameter thin wall copper tube, typically used for automotive brake lines. Unroll it into a spiral onto a wooden 'former' and by sliding the contacts up and down the spiral you can change the load. And, using something like an aquarium or car windscreen washer pump, (or just a hose off a kitchen tap) you can pump cold water up the middle of the tube to cool it. When i was developing a high current / low voltage DC/DC project this is what i used! --- End quote --- For brake line use, it has to be a certified copper-nickel alloy to be legal most places. For cheaper copper tubing, look in the plumbing section for the stuff used for ice makers or humidifiers. For cooling, just immersing the entire thing in fresh water is probably way easier than trying to get sufficient volume down the tube. |
| ocset:
You can make yourself an active dummy load by using fet set up as a current regulator....eg put sense resistor in its source and regulate the voltage across the sense res using an opamp set up as an integrator (error amplifier). And youll need a reference aswell. And you can parallel as many as you need. Put a heatsink on the fet(s) and thats it done..... this saves you haveing to buy loads of different value power resistors. |
| Seekonk:
I've used pipe strapping, the 1'' steel banding with a lot of holes in it, for shunts. Makes a pretty good resistor with a lot of surface area for getting rid of heat. |
| edpalmer42:
--- Quote from: Seekonk on July 15, 2018, 02:04:50 pm ---I've used pipe strapping, the 1'' steel banding with a lot of holes in it, for shunts. Makes a pretty good resistor with a lot of surface area for getting rid of heat. --- End quote --- +1 for this. And the holes make it very easy to connect copper cables with lugs. Just bolt them on. |
| lordvader88:
Well I ordered a big wire wound power resistor, 300W 1Ohm, so thats safe anyway. I haven't got the kettle from the basement yet. I half remember some equations from chemistry for heating water, I should do a proper experiment and find out. |
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