An article in Radio Electronics magazine from November 1958 showed the construction of this tube audio oscillator. Note the use of lamps as a stabilizer to obtain better sinusoidal signals.
Found in a publication for radio amateurs from the 1990s, this circuit makes it possible to...
I found this circuit in a Popular Electronics from November 1999. The magazine is no longer...
This simple transistorized receiver with earphone was found in a Japanese publication from the...