Bridge rectifier

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Hi Freaks,
I was looking at the STK500 schematics and wanted to know if the DC jack ground and the bridge rectifier ground can be made common?
Thanks.

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You can remove the bridge and short the ground and V+ (1&3 V+ 2&4 ground) BUT make sure you NEVER use an AC power pack with it and that your jack is wired up correctly.

It is a good idea to put a diode in series with V+ (1&3).

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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You could just connect bridge pins 2 and 4.

This will make the DC plug shell as GND, and you still have half-wave rectifier there.

The downside (or upside) is that then you have reverse voltage protection diode too, which shorts the input pins if wrog polarity is fed.

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@John,
Yes I have been using that configuration for my breadboard circuits.

My main purpose in using a similar design is so that I can connect any of those barrel connectors (within the voltage and current ratings,of course) to my board. Since the barrel connectors of the wall warts (the chargers you use for your cell phones)are not standardized, (body to ground, etc.), I would like to make sure any of those connectors will work for my board.

In other words, I want to make this design idiot-proof so that no matter what jack people use, the board won't vaporize.

I am welcome to suggestions for other similar bridge circuits if you guys know of any that will serve the purpose.

So if I used the exact same circuit, can I short the GND used for pin #2 of the bridge and the GND used on the DC jack?

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If you want to be able connect any wall wart no matter what polarisation you should use the STK500 circuit, there is no need to short pins.

Otherwise a plain diode is all you need to protect against wrong polarity.