For Eric: Question about CS6PI

[Anonymous]

Eric,
What is the effect of changing the main 555 timing cap from 1000nf (stock value) to about 680nf on the new frequency range and on sensitivity to various items?

 

[Anonymous]

Hi,
Best thing is to try it and see. The pulse delay, TX pulse and pulse frequency will all be affected and provided the coil can cope with the faster pulses, you will get more sensitivity to small items. There is always a production spread on coils as far as inductance and self capacitance goes so it may be OK or maybe not. You can always wind the frequency control back to get the normal minimum setting.
Eric.

 

[Anonymous]

I guess the real questions are: what is the original frequency with a 1000nf cap and what would the new frequency be with a 680nf cap?
I assume that based on circuit design paraments that only you would know, that the new higher frequency could be calculated or estimated subject to normal tolerances. What is this new higher frequency?
With the frequency control at its highest fully CCW position I seem to get about 14 inches on a U.S. nickel in an air-test after the cap mod. Quarters and dimes are about 10 inches in a air-test.
A slight CW frequency control rotation (2 numbers) quickly reduces the sensitivity on nickels and gold. Is this what you would expect?
It's good to be able to have a technical dialog with the designer of the CS6PI machine.
Thanks for your continued involvment with this forum.
bbsailor