Question on current using midin.

MIDIfication
1

Hi,

Can anyone tell me what the current is when using the Midin board to scan for stop tabs on / off.

I believe that there is a 5volt supply is switched to ground when a tab is turned on?

If that is correct what is the amount of current that flows?

I need this info in able to select a transistor to use as the switch.

Thanks,

Martin

2

???

well, hmmm, … what are you talking about ?

What is the “Midin board”, and what is “stop tabs” ?

I’m sorry but I dont have a clue what you’re talking about, am i the only one ?

3

Arnak wants to know how much is the current flowing when a DIN pin is clamped to ground cause he wants to use a transistor to act as a button and he doesn t want that transistor to burn out.. right?

4

Hi,

Absolutely correct. 8-))

I have just posted a reply hopefully making it a bit clearer.

Thanks,

Martin

5

Hi,

This is to control the stop tabs on an organ.

Using the core module and the DIN module.

I was informed that the module sent out a 5 volt signal so that when that 5v was switched to ground by for example pressing the stop tab down or by a reed switch on the pedal board then the key or stop tab was switched on.

To use that signal to detect the operation of a stop tab I am attempting to construct a touch sensitive stop tab which when it is touched the output from the touch circuit will supply a voltage into the base of a  transistor which will turn it on.

This will in turn allow the 5v from the DIN board to pass to ground and so turn on that particular stop tab.

In order to select the correct transistor I need to know the current that will be passed on that 5volt line when switched to ground.

Hope that makes things a bit clearer.

Martin

6

Well, better late than never.

I just checked, and each input on a DINX4 board is pulled up to

five volts by a 10K Ohm resistor.

So the current would be 5 / 10000 = 0.0005 Amps

This would more commonly be called 0.5 ma (milli-amps).

Since there are 32 inputs on a DINX4, this means we might draw as much as

16 ma just for the pullup resistors (if all were grounded at once).

All estimates are only as close as your resistor tolerance and your power

supply voltage tolerance.

Have Fun,

LyleHaze