novice need help ...

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gigiduru

Joined May 8, 2008
2
I need help to design a current generator with variable adjustable current values but once adjusted needs to be constant, while the load (7.4 ohm coil) may become hot and change the resistance. The current needs to be adjustable between 100 to 700 mA ( a pot. or a resistor divider will do it), power supply 12V and operate at military or automotive specs.
Any help will be appreciated.
:confused:
 

beenthere

Joined Apr 20, 2004
15,819
Get the data sheet for the LM317 adjustable regulator. One of the applications illustrated is for a current regulator.
 

SgtWookie

Joined Jul 17, 2007
22,230
In particular, National's datasheet for the LM117/LM317. Look at the bottom of page 18.

If R1=12 Ohms, Iout=100mA
If R1=1.7 Ohms, Iout=705mA
I suggest you use a 3-Watt rheostat for R1, with a 1.5 Ohm 2-Watt resistor in series.
 
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