Variable oscillator for code practice (CB7317E)

This circuit is from Popular Electronics from the 90s. The integrated circuit is not very common nowadays.

Photodiode amplifier LMV358A (CB20384E)
The operational amplifier used in this circuit is a low voltage type from Texas Instruments, being...
Mark generator (CB7526E)
Found in an English Maplin documentation from 1983, this circuit generates separate frequency...
Double Audio Oscillator (CB4524E)
The presented circuit consists of a double phase shift oscillator capable of generating two sine...