Re: voltage spike of AC power line

On Mar 4, 10:20 am, ***...@xxxxxxxxx wrote:
I was having false triggering on my LM393 input when I switch on the
lamp (tungsten or florescent) in my room. After experiment a bit, 2
ceramic capacitors(2200pF) at both LM393 input seems to solve the
problem. Why is there such a "switch-on" voltage spike & what is the
voltage frequency?

Thanks in advance
ck

Without the bypasses, the LM393 will respond to sub-microsecond
pulses.

With a 2200pF C on the inputs with circa 10k-ohm impedances, the time
constant is now 20 microseconds.

If the R is a megohm instead of 10K, the time constant with the 2200pF
bypasses is 2 milliseconds.

Does that answer your question about spikes? Or where the "false" in
"false triggering" lies?

Tim.
.

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