Not sure an LM7806CV actually exists. The datasheet search engines can't find it. Are you sure it says LM7806CV and not L7806CV or LM7806 with some other suffix?
That's the datasheet for an L7806CV, not LM7806CV
Hang on did you say LM7806----CV ????
SGS -Thomson Microelectronics website has this marked down as a -----
500ma regulator ---NOT a normal 1.5 amp LM regulator .
IF ---that is the case then the valve/tube isn't far short of the regulators limit and as several posters have said ---"is it LIMITING " ?
I said I use those - L7806CV - and the linked sheet implies 1.2A. The OP just said "7806".
Here it is again: https://datasheet.lcsc.com/szlcsc/2006070931_HGC-Huaguan-Semicon-L7806CV_C519075.pdf
TL;DR
5.0mA<Io<1.2A,Po<15W 5.7 6.0 6.3 V
Vi=8.5V to 21V
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Some "dodgy websites " like this one have it marked down as 7806-L7806-LM7806-
Jual TRANSISTOR REGULATOR 7806 L7806 LM 7806 CV TR IC PSU REGULATOR ASLI - - Solid Jaya Elektronik | Tokopedia
I am beginning to wonder where he bought the regulators India/ China and all points in between.
Jual TRANSISTOR REGULATOR 7806 L7806 LM 7806 CV TR IC PSU REGULATOR ASLI - - Solid Jaya Elektronik | Tokopedia
I am beginning to wonder where he bought the regulators India/ China and all points in between.
Nothing wrong with China - just know what you're buying. LCSC sells Asian, EU, and US parts, not knock-offs/counterfeits. If you see a BUZ901 for 4$ on eBay, it's fake. If you see a Huaguan L7806CV, it's legit because the patent expired and anyone with a fab can make them now. I'd rather buy Chengxing then fake/counterfeit Nichicon because I know the specs of the Chengxing part.
Apple make all their stuff in China and rarely do people complain about the quality...
Apple make all their stuff in China and rarely do people complain about the quality...
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I don't think the OP ever said 7806 until I just ask asked him.
You could be right - did we just assume all this time? What if they's using an LM317? LOL
Removed the output cap and replaced with 0.2uF - with 12.6 vdc on input getting 5.9vdc out with 18R load which is 328mA, it's NEVER been that high ! Could the output cap be responsible ?? With 10R load output is 4.88vdc - you may have nailed it Duncan !! if so I was miss sold these as 1.5A devices, the regulators I have subsequently ordered are supposedly rated at 2A. Is 5.9vdc reasonable ( 328mA ) if these are indeed 0.5A devices ?
Yes. It can cause instability if the output cap is too large. 5.9V is within spec - 5.7V - 6.3V is the spread. If you want more voltage, you can "lift" the 7806 by putting a diode in the pin 2 leg (lift it off of ground by Vf of the diode) Said diode must be rated for the full load current..
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With one valve connected it's crept up to 4.84vdc, when the new regulators arrive I'll post results, till then thanks to every body for all your help. lesson learnt - don't always believe what your sold !!
I'm not reading an adequate explanation for your results, I suggest you answer our follow up questions. Plus a 2A rated TO-220 fixed LM regulator sounds fake.
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That was post #29Post a picture of your setup, and a close up of the regulator clearly showing the writing on it.
Sid
Got the new regulators yesterday and BINGO 5.86vdc with 3 valves connected and powering up almost instantly ! Phew, so what have I learnt - read the feedback on ebay, it's there for a reason.
74 posts and it was the cheap/nasty regulators .
I would like to say buy dear but the scammers are up to that too ,its down to buying from websites/companies that sell reliable and genuine electronic parts.
You have probably learned somethings practical about voltage regulators and their workings which should stand you in good staid --good luck .
I would like to say buy dear but the scammers are up to that too ,its down to buying from websites/companies that sell reliable and genuine electronic parts.
You have probably learned somethings practical about voltage regulators and their workings which should stand you in good staid --good luck .
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