Found in a Popular Electronics from the 90s, this circuit activates a recorder for automatic recording of telephone calls. The circuit was used with old cassette recorders of the time.
This circuit is an application note from Texas Instruments, generating a signal of 1.57 kHz given...
Found in a Popular Electronics from the 90s, this circuit activates a recorder for automatic...
This filter has a cutoff frequency of 0.026 Hz given by R and C. These components can be...