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My electronics knowledge is a bit rusty! +/- 15v Power Supply. Please help

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m4hill

New Member
Hello.

1st time posting on these forums. I did electronics at a-level, but haven't done anything for a good 10 years so most of the stuff i learnt, i've completely forgotten.

I need to supply split rail power of +/- 15v. The power requirements aren't that great. I'm only powering a quad op amp and 24 led's

I currently have a bench psu capable of producing 30v dc, but it won't work as a dual output supply, even though i was assured it would!

I have read about virtual grounds which i could use to produce a split rail supply.

If a virtual ground is not suitable, then could someone point me in the right direction for building one using a transformer and some sort of rectification for both positive and negative supplies. I guess i'd use the centre tap as the ground.

Cheers
Martin
 

zipdogso

New Member
Hello.

1st time posting on these forums. I did electronics at a-level, but haven't done anything for a good 10 years so most of the stuff i learnt, i've completely forgotten.

I need to supply split rail power of +/- 15v. The power requirements aren't that great. I'm only powering a quad op amp and 24 led's

I currently have a bench psu capable of producing 30v dc, but it won't work as a dual output supply, even though i was assured it would!

I have read about virtual grounds which i could use to produce a split rail supply.

If a virtual ground is not suitable, then could someone point me in the right direction for building one using a transformer and some sort of rectification for both positive and negative supplies. I guess i'd use the centre tap as the ground.

Cheers
Martin
My commiserations at spending out that much dosh.....if only you had just scrolled down to the specs all would of been revealed ... 0v -27.6v nothing about dual output at all and I know that SOMETIMES (certainly not all.) Maplin have their heads up their bottoms.
Dual output supplies often have 3 sockets negative, ground, and positive you use the Neg. and pos for AC and the ground and pos for DC.
What's more if you'd of googled instead of just going to Maplin you'd of got one cheaper !!!
Can't you return it ?
 

k7elp60

Active Member
Hello.

1st time posting on these forums. I did electronics at a-level, but haven't done anything for a good 10 years so most of the stuff i learnt, i've completely forgotten.

I need to supply split rail power of +/- 15v. The power requirements aren't that great. I'm only powering a quad op amp and 24 led's

I currently have a bench psu capable of producing 30v dc, but it won't work as a dual output supply, even though i was assured it would!

I have read about virtual grounds which i could use to produce a split rail supply.

If a virtual ground is not suitable, then could someone point me in the right direction for building one using a transformer and some sort of rectification for both positive and negative supplies. I guess i'd use the centre tap as the ground.

Cheers
Martin
You probably do not need a split supply. Look at this http://www.electro-tech-online.com/threads/basic-opamp-circuits.35258/
Post your circuit, there is lots of help here.
 

m4hill

New Member
I took it back to maplin and got my money back.
Then i spent £6 building my own power supply. Does the job great!
 

bountyhunter

Well-Known Member
could someone point me in the right direction for building one using a transformer and some sort of rectification for both positive and negative supplies. I guess i'd use the centre tap as the ground.

Cheers
Martin
You got it nailed. Get a 32VAC (secondary) center-tapped transformer with current rating of maybe 0.5A or more. Ground the center tap, hang a rectifier on each lead in the correct direction and add a filter cap for each side and a 7812 and 7912 and you got it made. The data sheets for those parts probably have example circuits.
 
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