[time-nuts] minimalist sine to square

[cdelect at juno.com]

The Efratom/Tektronix  PTB-100 took the 10Mhz sine out of the FRK brick,
AC coupled it to the input of an 74LS14 biased with a votage divider from
+5 to ground.

4 parts!

Cheers,

Corby