Hello,
I'm hoping to build a giant (500mm) slider potentiometer for an electronic musical instrument.
I'm going through some scenarios, and it seems like for a 100k ohm resistor, I'll need a wire with something like 8k ohms per foot. Does that seem right? I can't find any such material... Here's where I got that number:
I plan to wrap the wire around a 6mm diameter non-conductive rod.
Let's say the wire is .8mm diameter— that's 625 wraps around the rod (500mm/.8mm), and just under 19mm for the circumference of the rod (6mmx3.14), so 625 turns x 19mm per turn = 11.875m of wire to wrap along the length of the rod. If I want there to be 100k ohms across that length, I'll need 100k ohms / 11.875m = 8,421 ohms per meter... right? (I'll admit math was never my strong suit.)
What sort of wire is used in professional wire-wound potentiometers? It seems nichrome wire doesn't get anywhere close to that sort of resistance. Are you aware of any sort of wire material with an abnormally high electrical resistivity? Somebody mentioned somewhere that spark plug wire is carbon at the core, and if stripped it might have a high resistance— does anybody know if this is true (I'm wondering this more for a separate project/idea)?
Any help or input is greatly appreciated.
Thanks,
Jason
I'm hoping to build a giant (500mm) slider potentiometer for an electronic musical instrument.
I'm going through some scenarios, and it seems like for a 100k ohm resistor, I'll need a wire with something like 8k ohms per foot. Does that seem right? I can't find any such material... Here's where I got that number:
I plan to wrap the wire around a 6mm diameter non-conductive rod.
Let's say the wire is .8mm diameter— that's 625 wraps around the rod (500mm/.8mm), and just under 19mm for the circumference of the rod (6mmx3.14), so 625 turns x 19mm per turn = 11.875m of wire to wrap along the length of the rod. If I want there to be 100k ohms across that length, I'll need 100k ohms / 11.875m = 8,421 ohms per meter... right? (I'll admit math was never my strong suit.)
What sort of wire is used in professional wire-wound potentiometers? It seems nichrome wire doesn't get anywhere close to that sort of resistance. Are you aware of any sort of wire material with an abnormally high electrical resistivity? Somebody mentioned somewhere that spark plug wire is carbon at the core, and if stripped it might have a high resistance— does anybody know if this is true (I'm wondering this more for a separate project/idea)?
Any help or input is greatly appreciated.
Thanks,
Jason