Found in a Popular Electronics from the 90s, this game can be seen in other configurations on this site. The circuit uses components that are still common today.
This simple 4-bit digital-to-analog converter was found in a 1974 publication. The transistors can be the...
I found this circuit in an American magazine Hands On Electronics from September 1987. The...
Of course, the current is extremely small, but a voltage of 300 V can be obtained from 9 V of a...