This circuit was found in a 90s American publication. The same configuration appears in several places on this site, obtained from different sources. The lamps can be replaced by LEDs.
This buffered version of the previous circuit appeared in an article in the September 1989 Radio...
This circuit consists of an improved version of the CIR5892, using two transistors and adjusting the...
This circuit was found in a 1977 Signetics manual. The 556 consists of a 555 double and the...