Milliamperes Source Circuit Diagram

Very simple is: 24V/1mA= 24Kohm; 24V/500mA= 48 Ohms. So series connect potentiometer of 0 to 24Kohm to your 24DC source! Pot wattage must be above 24VX24V/ 48Ohms = 12 watts.

Use a LM317 regulator in current source mode you should be able to get the current range your after with some judicious component selection.

Just using a potentiometer is no good unless it can dissipate successfully the heat generated.

"Source" here you mean 500mA.

It is called a "Current-Source"

Supply and Source are different terms.

Source is a constant current at varying load; not on a fixed load.

So input power source should be able to maintain contant current to both limits i.e.

Min & Max limit of Load impedance.

Read the link above.

I

Try the Linear Technology LT3092. You can use just one to get up to 200mA, or you can parallel two or more devices to get more current. See pages 12 and 13 of the data sheet.

Many benchtop power supplies come equipped with adjustable current limits. With careful turning of this adjustment knob, you should be able to get the power supply to regulate to the amount of current you need to test an actuator. Set the voltage adjustment to maximum, and use the current adjustment to regulate current to the actuator. Be sure to use a multimeter to measure current (i.e. don't trust the built-in ammeter in the power suppy, as these usually lack the necessary resolution).