Obtained from an English publication in the 1980s, when a weather station operated in that country at 60 kHz, this circuit employed only two general-purpose transistors.
We found this circuit in an old documentation from 1988. The circuit captures the heartbeat...
This circuit was found in a Popular Electronics from the 90s. The transistors are general purpose, and...
This circuit is from a documentation from the 70s. The transistors are types of germanium of the...