DC power Jack - A basic Question

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Hi,

I am building a board where the power input can come from a battery or an adapter. So, I used a 3-polled DC jack and the schematic depicted below. My aim is that when a plug is connected to the jack, the Battery GND signal will be disconnected. When the plug is taken out again, the Battery GND is connected again and the circuit contiunes getting power. Does the circuit in the schemtic work?

Thank you,
JJ

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Depends on how the supply adapter is wired; you need to check it, the ring might be ground.

Leon

Leon Heller G1HSM

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leon_heller wrote:
Depends on how the supply adapter is wired; you need to check it, the ring might be ground.

Leon

Thats then a matter of reverse polarity protection, isn't it? A short circuit can't happen because the battery GND will be isolated.

JJ

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A strange question to ask. For one, we don't know the exact part you're using for the connector, so any comment we make is purely academic. Yes, it looks like the circuit will work, as to whether it works as advertised with your actual connector and wiring - only you can determine this. I would suggest you wire up said circuit and test - the answer will be clear.

And I'd be putting some reverse polarity protection in.

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I had a very similiar question answered here: https://www.avrfreaks.net/index.p...

:)

Chief Tinkerer

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triden wrote:
I had a very similiar question answered here: https://www.avrfreaks.net/index.p...

:)

Thanks alot Triden! It's nearly the same question. So, this is how you do it:

pin 1 is connected to GND.
pin 2 is connected to the Battery.
pin 3 is connected to the device electronics.

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why dont you test that circuit? and find out.. instead of useing a large bat use a smaller battery just one to light a led, and for the DC jack use also a small voltage.. see if the LED flickers... you might also want to attach a volt meter too is, and see if when the power is being switched, it doesent overflow the circuit for a split second, might cause a prob if you running chips on it... if thats the case, im sure you could just use a voltage regulator, im sure you will be putting one of those in circuit anyways...

Im not master elect. but it seems like a simple enough circuit.. I just say test.. dev.. test.. and remember you can never protect your hardware to much.. so.

EDIT: mabye want a couple of strong z.diodes in circuit as well make sure they are flowing into each other.. may help balence things out for that split second when you connect. i dont know.

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Quote:

pin 1 is connected to GND.
pin 2 is connected to the Battery.
pin 3 is connected to the device electronics.

Also before doing that make sure the power source your using is indeed ground as 1, because not all DC jacks have the same polarity. im sure you know this already.

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ph0rkeh wrote:
Quote:

pin 1 is connected to GND.
pin 2 is connected to the Battery.
pin 3 is connected to the device electronics.

Also before doing that make sure the power source your using is indeed ground as 1, because not all DC jacks have the same polarity. im sure you know this already.

Thank you ph0rkeh, thats true. A diode in series might solve this problem.

JJ

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I have one last question regarding the names of pins. I am using this power Jack (Switchcraft RAPC722, see picture below) Im confused about the naming of the pins. It lists the three pins as: Center pin terminal;shunt terminal; and sleeve terminal, but the question is which one is which? You think the schematic I posted below is right?

Thank you,
JJ

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Is it ok for the power to drop out while you are doing the plugging and unplugging? The power is going to flicker and bounce like crazy when you plug and unplug.

Go electric!
Happy electric car owner / builder

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sgomes wrote:
Is it ok for the power to drop out while you are doing the plugging and unplugging? The power is going to flicker and bounce like crazy when you plug and unplug.

thats also what I had in mind. what are you going to be running on this circuit?

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ph0rkeh wrote:
sgomes wrote:
Is it ok for the power to drop out while you are doing the plugging and unplugging? The power is going to flicker and bounce like crazy when you plug and unplug.

thats also what I had in mind. what are you going to be running on this circuit?

I am not going to switch powers while the device is ON. But if I wanted that, I think large bypass capacitors in parallel from VCC to GND will filter these flickering.

JJ

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Oh if your not going to switch when powers on, then I dont see why your circuit wouldent work at all... just take a multimeter, check witch 2 pins are connected when not plugged in, make sure that witch ever 2 that do connect when not plugged in, that those are both ground (1 from jack 1 from bat)..

with the DC jacks I use the 'terminal sleeve' on datasheet image is the one that drops out when plugged in.

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ph0rkeh wrote:
Oh if your not going to switch when powers on, then I dont see why your circuit wouldent work at all... just take a multimeter, check witch 2 pins are connected when not plugged in, make sure that witch ever 2 that do connect when not plugged in, that those are both ground (1 from jack 1 from bat)..

with the DC jacks I use the 'terminal sleeve' on datasheet image is the one that drops out when plugged in.

The problem is I don't have this DC-Jack right now to figure that out and I am supposed to design a PCB layout for it. If I had the jack, I wouldn't have asked on the first place. :)

JJ