direct current stimulation

[mihov123]

I do not know much about eletronics, but I get around
Could you please help me with this

direct current stimulation
I need a battery powered constant current output of 1-2 mA,I have an Idea how to make this,
but I do not know how to cope with the skin resistance

It is important that the device is current controlled. What this means is that the device will adjust
the voltage up and down as the resistance changes so that the current never changes. For instance, if the
resistance of the skin is 10,000 ohms, then 10 volts will be needed to “push” 1 ma through the body. If for
some reason, the connection becomes poor and jumps to 20,000 ohms, then the device should
automatically increase the voltage to 20 volts in order to push the 1 ma current through the body.

Could could you tell me what I need to do, or give me a circuit similar to what I need.

Thank you

 

[jackorocko]

Inductors resist changes in current. I am sure there is also current regulating IC's just like voltage regulators.

 

[Resqueline]

In a simple form a constant current "generator" can consist of only two transistors & two resistors. Inductors are only used for smoothing higher frequency currents.

 

[(*steve*)]

There are also "constant current diodes" which are just jfets with their gate shorted to their source (gives a constant current often specified as Igss. Note that tolerance spreads for jfets are quite high and the current may vary significantly from one jfet to another (even when they come from the same manufacturing batch).

Here is some more information.

These devices are available as 2 terminal devices that have already been sorted for current.