Hey guys,

Question on Alligator clips..

If i'm running a signal at 500KHz, would the use of an alligator clip cable introduce any significant inductance? i'm sure it depends on the clip itself, but generally.. ?

Thanks

 

The partial self-inductance of a wire is about 25nH per inch. Keep in mind that current always flows in a loop, so you need to include your return current path as well. Whether this is significant in your case depends (at least) on circuit impedances and wire length.

 

what about the clips themselves? say i have a relatively short wire (15 cm say), do the ridges of the clips introduce a significant inductance at 500khz? like, do the ridges count as a "loop" of wire?

 

while the frequency may be 500kHz, you don't say what the current is, what sort of circuit you are tapping into and finally what sort of accuracy you are after. If you are tapping extra capacitors in across a circuit of Q=500+, then the croc clips wil effect the resullts, if you are just coupling a signal generator into the input of an OP-amp then you can neglect the crock clips. It also depend if the clips are plated steel or plated brass.
Frank

 

http://en.wikipedia.org/wiki/Skin_effect

So... how big are the teeth?

 

what about the clips themselves? say i have a relatively short wire (15 cm say), do the ridges of the clips introduce a significant inductance at 500khz? like, do the ridges count as a "loop" of wire?

The ridges are insignificant. The overall length of the alligator clip could be thought of as wire length. Capacitance might be an issue (probably not), depending on what sort of circuit you are connecting to. As Frank said, we need more info.
15 cm of wire (is that the loop length?), plus maybe 5 cm for the length of two alligator small clips, would give you about 200nH of inductance. At 500kHz, that's about 0.6 ohms reactance. If you're talking about a 500kHz sine wave, or 500kHz bandwidth, then probably not a problem. If you have a 500kHz pulse waveform with fast rise times, 200nH will be significant.