Dc barrel and battery

[Guitarist335]

I am trying to wire a DC barrel with. 9 volt battery clip and led.  I can't figure out how to wire it. Can anyone help.  I want it so that the battery is disconnected when the dc is engaged, and the led lights up when the effect is on, regardless of the power source.


Thank you

[Rob Strand]

You want the input jack to switch the negative and the DC jack to switch the battery positive.

*** note the ground on the DC jack can go to the circuit or to the input socket.  It depends if you
want the jack power to stay on when you pull the input plug.  As shown the jack power stays on.


You can see the switching on the barrel, it's normally closed which passes the battery.  The important thing is to work out which one goes to the + on the DC jack and which one is switched, which goes to the battery.

[Guitarist335]

Thanks Rob

[Guitarist335]

I must have a mind block.

Here is what I have so far:

The right + lug of the DC Barrel  runs to the + of the battery clip

The middle + lug of the DC Barrel has two wires coming out of it. One goes to the step down resistor that connects to the + side of LED. The other lead goes to the circuit board to feed it 9V at the voltage divider circuit.

The - side of the LED runs to the stompswitch (top row, middle lug).   The - side of the LED also runs to ground.


Here are my results:

When I plug in the battery, the LED lights up when the effect is activated through pushing down the stompswitch. When I turn off the effect by pushing down the stompswitch, the LED turns off. (so far, so good)

Here is the problem.

When I plug in a 9volt adapter plug, to the DC barrell, the LED lights up, but stays lit no matter whether the stompswitch turns the effect on or off.

I assume that the LED should turn off, if the DC barrel is powering the pedal, but the effect is turned off.

Can anyone suggest why it is staying on, and what I should do to correct it?

Thank-you.

[r080]

The - side of the LED runs to the stompswitch (top row, middle lug).   The - side of the LED also runs to ground.

I don't think you want both of these to be true. The LED connection to ground should be through the footswitch only.

[anotherjim]

You do want the LED switched by the footswitch.
DC connector -
The lug with the big rivet is the centre contact pin (negative DC supply)
The lug nearest to that is the switched contact (battery +)
The furthest lug is the outer plug contact (positive DC supply).

[Ice-9]

The - side of the LED runs to the stompswitch (top row, middle lug).   The - side of the LED also runs to ground.

I don't think you want both of these to be true. The LED connection to ground should be through the footswitch only.

This...... The -side of the led should run to the footswitch and the footswitch switches the LED -side to ground. No need to directly run the -side of the LED ground as it would always be ON.

[Guitarist335]

Thanks to all. Based on your advice, it works now.