07 March 2012

A coil or a lifelong supply of enameled wire

While the supercapacitor and white LED in the handshake flashlight have been used to build a proof-of-concept USB rechargeable flashlight, the coil is now calling for attention. A passive audio filter came to my mind.

On my DVM the coil measures ~22mH for 100 ohm of wire resistance. At 1kHz this means a coil Q of 1,3 (Q = 2 * pi * f * H / R).

I am not into passive audio filters but the Q sounds too low to be useful. The other option would be to use the coil as a lifelong source of enameled copper wire. According to the perceived diameter (not measured, but it is thin) I would have about 1km of wire!