Same thing, no diference...

The count becomes better using a high pass filter, with a 470nF and a 12k resistor. This means low freq. noise... like the 60Hz of the 120vAC (in Brazil is 60Hz). Is not 100% stable but working a little more on the filter will be ok (I hope so).

I really don´t know that the 873A was SO sensible to noise. I´ve used the 628A without any problems...

Originally posted by Bruce
Out of curiosity, how stable is the count if you disable interrupts?