Two 9V Wall warts for 18V ????

metron9

I need 18V DC for a project of course RS had no 18V supplies, I was going to use a voltage regulator and a 36V (Only higher one they had) but decided 2 9V would do it
I thought it should work but it is not working.

WartAneg

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WartApos-WartBneg

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WartBpos

I only get 9V

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Think outside the BOX!

SPENCE

Can't make it out from the pictures but you have to wire them in series..
18vdc - or ground to neg side of number 1
plus side of number 1 to minus(neg) side of number 2
plus side of number 2 to 18vdc terminal.

Should work ok......

Check each one with a volt meter. Looks like you have it wired correctly.

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73
spence
k4kep

metron9

Yep it's wired correctly But I only get 9V on one supply connector and the rails are 9V but the other connector reads 0V. When I only plug in one supply and test the connector it works in each one.

Perhaps because they are regulated supplys.

Indeed, I happen to have another 9V 300ma supply that reads 15V (no load) I used that one with the regulated supply and around 25V (no load) so it must be because they are regulated supplys.

So if I use an 800ma 9V and a 300ma in series I spose I should only expect the weakest link of 300ma to be my max draw?

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Think outside the BOX!

metron9

God I can't believe I am so stupid

After learning that there was indeed 390 mA flowing from the Positive of one wart to the negative of the other wart I said Hmmmm somthing is not right

Of course it's not, both of the connectors are connected to an aluminum panel and thus are both connected to ground shorting out one of the warts


Geeeesssssssssss

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Think outside the BOX!

metron9

Now thats better and with indicator lights as well, who could ask for anything more?

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Think outside the BOX!