Despite being from a 1969 publication, the transistors used have current equivalents such as BC548 and BC558. The circuit generates signals from 1 500 to 20 000 Hz and 4 scales.
This circuit with only two transistors is from an 80's EDN. It can be implemented with two current...
This circuit that uses only discrete components (transistors) mimics the sound of an American...
This circuit is from Dutch documentation from 1967. The circuit works with a component of the...