[sdiy] My awesome DIY Christmas gift

[Magnus Danielson]

Paul Schreiber skrev:
> Counts AC line frequency.

Not much worse than many other clocks. I have a frequency counter that 
does the same, but mine has the crystal option which is a 100 kc/s 
oscillator (kept it in original language). That counter is in the 
pre-Nixie generation. :)

I really like the phantastron circuit. As I recall it, the division 
between net frequency to 10 Hz and 1 Hz only takes up 3 tubes. To 
support 50 Hz and 60 Hz they provided a trimmer at the back of the 
counter. When using the 100 kc/s oscillator, this is tuned to properly 
divide 100 Hz instead. The 100 kc/s oscillator option includes a 
oscillator core and a division by 1000 using three phantastron circuits 
in series.

Phantastron circuits should be possible to achieve in transistors designs.

Cheers,
Magnus