This circuit from a Popular Electronics from the 90's can generate signals from 0.03 Hz to 3 kHz depending on the value of the capacitor and resistor.
Found in a 1966 documentation, this mid-wave receiver makes use of period germanium transistors. The phone...
With an 18 V input, this regulator was found in Philips documentation from the 60's. The...
Despite being from a 1969 publication, the transistors used have current equivalents such as BC548 and...