This simple circuit makes use of neon lamps to indicate the voltage of a power grid. The lamps are common neon and the circuit indicates whether the voltage is 110 V or 220 V.
We found this circuit in an old Mullard (Philips) documentation on the 555 and 556 integrated circuit...
This adding amplifier with the operational LM324 is from the SGS integrated circuits manual of...
This divider by 6 is synchronized because it is implemented based on TTL or CMOS logic according to the...