This interesting circuit for SMD assembly appeared in the November 1987 issue of Radio Electronics magazine. The phonons are generated by selected resistors that are fitted to the assembly.
Found in a 90s Radio Electronics, this circuit is intended to drive a neon lamp from a 9 V source....
This simple tester was found in a Popular Electronics from the 90s. The circuit is powered by two...
Electronics Now from the 90's suggests this pulse conditioner circuit for use in tachometers. The...