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Voltage Regulator help

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xbearxau

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Im making a 9volt regulated supply for my guitar effects pedals.
Ive got a 12volt transformer thats capable of delivering 2 amp continuous load and Ive got a few 7809 9v 1A regs on hand. Can I parallel 2 of these to give me an available 2A load? Basically just joining the 2 outputs together?
Cheers,

Gaz.
 
why do you think you need to support 2A. If it's because the transformer can supply 2A, you are chasing down the wrong path.

Basically, the circuit being powered defines how much current it draws, not the voltage source. So, if your effects pedal draws 200 mA, then that's all you need to worry about (plus a 25-50% safety margin) and you only need one 7809. So figure out what the pedals draw (it might be on the specs or you could measure it with a DMM in amperage mode). If they run off of a 9V battery then a 1A supply will be more than enough - way more. A 9V alkaline battery would be dead inside of a half hour at a 1A draw. here's a link to the energizer 9V battery spec https://www.electro-tech-online.com/custompdfs/2007/10/522.pdf
 
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Thanks for the reply. My load is going to be about 1.5-1.6 amps, hence the request for a 2A supply to give me some headroom. 5 effects, tuner and a small light globe.

Sorry should have been more specific.

On a side note tho, I just finished hooking the 2 regs together and I get to about 2.8A of current draw before they cut out, with a dummy load and my multimeter in series. So it seem that it does work.

Cheers,
Gaz.
 
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Although your paralleled regulators are working, I think you will find it is not recommended practice - and may lead to early failure.
(basically the outputs are not exactly the same voltage)

There are 9v 2A regs out there, but perhaps not readily available where you are.
Suggest you buy one of the more popular 2 or 3 A variable regulators like the L200, just need a couple of extra resistors to control them.
 
Thanks Richard, I could buy the "right" parts, but I just happened to have these at hand. Ill buy the right regs next chance I get.
Thanks for your help guys.
 
As richrad.c points out, paralleling regulators is not a recommended solution. I would suggest adding a suitable transistor to increase the output current of your 7809.

This datasheet explains that tecnique with circuit equations (see Figure 14).
 
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Just use an LM217, it'll give over 1.5A.
 
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