Shortening pulses with an inductor

[McKendrigo]

Hi everyone,

quick question - I have been using a pulsed driver to pulse an LED. By placing an inductor in parallel with the LED, I can shorten the duration of the pulses from the LED. I'm looking for an explanation as to why this is the case...

I'm guessing that the inductor act as a high-pass filter, passing the high frequency components of the electrical pulses to the LED, and blocking the low frequency components (i.e. sending them to ground) - having the overall effect of reducing the time duration of the pulse from the LED.

Does that seem sensible? Thanks in advance for your help!

 

[vk6kro]

That sounds like the normal effect you get with an inductor when you apply a pulse to it through a resistor.

The effect varies with the frequency and the size of the inductor.

The green trace is the voltage across the inductor and the white one is the applied pulse from a function generator.

 

[Bob S]

Why waste output current with a parallel inductor when a series capacitor will do the same thing? A parallel inductor on a voltage source output will wreak havoc and add I²R heating on the output circuit of a voltage source.
Bob S