Using the 741 this circuit can be adjusted to values between 1 Hz and 100 kHz. The power supply must be symmetrical. We found it in the Radio Electronics magazine of November 1973.
An oscillator whose frequency can be adjusted between 500 Hz and 5 kHz with the use of a...
This circuit was found in Motorola documentation from 1969. The transistors are from that time. The...
This circuit brings together in a single set a preamplifier and an equalizer with several inputs. The...