Practice code oscillator (CB21090E)

Found in Popular Electronics from the 90's, this circuit consists of an audio oscillator for Morse code practice.

Extreme Ten60Power High Current Connectors
August 2017 - Mouser Electronics is making available the new Molex EXTreme Ten60Power ™ high...
High-Speed Modulated Light Receiver (CB24489E)
Modulated signals up to a few megahertz can be detected with the circuit shown in the figure,...
High impedance preamplifier 2 (CB20260E)
This circuit consists of an improved version of the previous circuit having an additional...