- Transformerless PSU using a capacitor - 4 Updates
- can I mount a stereo amplifier vertically - 1 Update
| "fynnashba@yahoo.com" <fynnashba@yahoo.com>: Jul 30 11:29AM -0700 Please I have to make a transformerless power supply using a capacitor. I have made the circuit and its working well, my problem is how to measure the current when its on load and the no-load current. When I use the normal way of measuring current the meter is not stable at all. Please how do l do it. Also for academic purpose how do I calculate the current drawn by the load (the load is a relay) What are the advantages of using the transformerless PSU(using a capacitor) thanks |
| Phil Allison <pallison49@gmail.com>: Jul 30 07:06PM -0700 fynn...@yahoo.com wrote: ------------------------------- > Please I have to make a transformerless power supply using a capacitor. > I have made the circuit and its working well, my problem is how to > measure the current when its on load and the no-load current. ** Our problem is we cannot see you damn circuit !! Is there one diode or a bridge ? Is the rely coil switched on and off or shorted to disable ? .... Phil |
| Tim R <timothy42b@aol.com>: Jul 31 06:29AM -0700 Seriously? bringing your class homework here? |
| "Dave M" <dgminala@mediacombb.net>: Jul 31 09:59AM -0500 A few questions to you first, to get an idea as to what you want to do, and what you've done so far. Are you trying to make a DC power source or an AC source? Is the load the relay coil or a load that is being switched by the relay? What kind of instrument are you using to measure the current, and how are you hooking it into the circuit? Is the relay a DC or AC relay? DC and AC relays are built differently, so they have different characteristics. If it's a DC relay coil, then just measure the coil resistance, divide that value into the voltage across the coil and you'll know what the current should be. If it's an AC relay coil, then you really need the Mfr's specs to know how much current the relay coil will draw. It's not just the coil's DC resistance that determines the current; also the coil inductance. Cheers, Dave M |
| Tim R <timothy42b@aol.com>: Jul 31 05:30AM -0700 Huh. Interesting ideas. I don't know where the air travels now. It might be worth borrowing a smoke tester and checking. It would be useful to know which component in an amplifier generates the most heat and therefore convective air flow, and which component is most sensitive to overheating. I'm assuming they are not the same component. |
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