Found in an 1868 Mullard documentation this circuit has a dynamic range of 10 Hz to 25,000 Hz. Modern equivalent transistors can be used.
The circuit shown in figure 5 generates square signals based on a transconductance operational amplifier...
By adding a transistor to the output and some polarization features we can obtain a higher output...
Found in the 1990 special issue of Radio Electronics Experimenter magazine, this circuit uses an...