iiiibadboyiiii Posted November 10, 2005 Report Share Posted November 10, 2005 hi...i spent almost the whole day 2day building a cigarette lighter plug adaptor which i could use to power my minidisc player (sharp md-mt90) while im in the car...so i used a LM7805 and a small cap (and added a small led as indicator), tested the output and it was exactely 5.08V. So i plug it into my md, but nothing... try the original wall plug adaptor and that still works fine. so i test the output of the original adaptor and get 5.61V. so i rebuild my adaptor and add a diode between ground and the ground pin of the 7805 and test the output again: 5.69V. I plug it in the md and guess what...nothing againcheck on the net and i find a car adapter which i could order (50$, but they dont deliver to South Africa) and under the technical details it says 4.5V. Rebuild again and measure 4.43 Volt but it still didnt work on my MD.i tried running the md off the battery, and while its on, plugged in my adaptor, but the battery icon goes off for 1 sec and then turns on again....any help would be appreciated!btw, the wall plug says 800mA on it... but the 7805 gives max 1A so that shouldnt be a problem.... or maybe???do these voltages matter that much??? i mean its like 0.07 and 0.05V difference in most cases...thanx Quote Link to comment Share on other sites More sharing options...
iiiibadboyiiii Posted November 11, 2005 Author Report Share Posted November 11, 2005 hi everyone...problem solved!the plug which went into the MD had a fault and only worked when held at a certain angle.my adaptor powered the MD fine with a simple LM8705 and a zener diode attached between ground and the common connector of the voltage regulator.rene Quote Link to comment Share on other sites More sharing options...
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