current Driver - Electronic Circuits Projects Diagrams Free

Pao · 23rd September 2006, 12:45 PM

hi guys,

need help finding a variable current driver circuit.
thanks in advance

Pao

**Nigel Goodwin** · 23rd September 2006, 01:00 PM

Again, give more information - such as what range of current, and to do what!.

Pao · 23rd September 2006, 05:26 PM

i need a 0-20mA variable current driver that a sawtooth waveform of 250hz and 1hz and a squarewave of 1-100hz can pass. Ranging from 1-10V. I need it cause i have a project or should i say for extra credit to make a dead frog leg kick using the schematic below but apparently it lacks current seeing that it only powered by a LM324.

I know what you guys are thinking why not change the whole circuit instead of putting a current driver right? Well one reason is that the hint/ requirement my teacher gave is that we cannot change the said circuit. And 2nd I have no background or idea on how a current driver works, its a good opportunity to learn. Although Im currently researching for it. so thankz

**Nigel Goodwin** · 23rd September 2006, 06:33 PM

What's the reason for IC10?, presumably it's supposed to be a constant current source?, but isn't your whole objective to provide a varying current?.

However, a simple NPN transistor, base to the three diodes, collector to +12V, will provide a higher current drive from it's emitter.

Pao · 24th September 2006, 03:37 PM

IC 10 was supposedly a current limiter of 20mA but it doesn't work.

**Nigel Goodwin** · 24th September 2006, 06:26 PM

Quote:

Originally Posted by Pao

IC 10 was supposedly a current limiter of 20mA but it doesn't work.

I wouldn't expect it to!.

Pao · 25th September 2006, 03:27 PM

Quote:

Originally Posted by Nigel Goodwin

I wouldn't expect it to!.

LoL well i did and got burned with it. My friend that gave that circuit now has the nickname LMspecialist LoL
got any suggestion on NPN X'sistor i could use i found this NZT651 but Im not too sure.

**Nigel Goodwin** · 25th September 2006, 04:38 PM

Any small signal NPN should do, and use a resistor for a current limiter!

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23rd September 2006, 12:45 PM	#1
Pao	current Driver hi guys, need help finding a variable current driver circuit. thanks in advance Pao

23rd September 2006, 01:00 PM	#2
Nigel Goodwin	Again, give more information - such as what range of current, and to do what!. __________________ PIC programmer software, and PIC Tutorials at: http://www.winpicprog.co.uk

23rd September 2006, 05:26 PM	#3
Pao	i need a 0-20mA variable current driver that a sawtooth waveform of 250hz and 1hz and a squarewave of 1-100hz can pass. Ranging from 1-10V. I need it cause i have a project or should i say for extra credit to make a dead frog leg kick using the schematic below but apparently it lacks current seeing that it only powered by a LM324. I know what you guys are thinking why not change the whole circuit instead of putting a current driver right? Well one reason is that the hint/ requirement my teacher gave is that we cannot change the said circuit. And 2nd I have no background or idea on how a current driver works, its a good opportunity to learn. Although Im currently researching for it. so thankz Attached Thumbnails

23rd September 2006, 06:33 PM	#4
Nigel Goodwin	What's the reason for IC10?, presumably it's supposed to be a constant current source?, but isn't your whole objective to provide a varying current?. However, a simple NPN transistor, base to the three diodes, collector to +12V, will provide a higher current drive from it's emitter. __________________ PIC programmer software, and PIC Tutorials at: http://www.winpicprog.co.uk

24th September 2006, 03:37 PM	#5
Pao	IC 10 was supposedly a current limiter of 20mA but it doesn't work.

25th September 2006, 04:38 PM	#8
Nigel Goodwin	Any small signal NPN should do, and use a resistor for a current limiter! __________________ PIC programmer software, and PIC Tutorials at: http://www.winpicprog.co.uk