This variable frequency circuit was found in a Popular Electronics from the 90s. The circuit outputs to a small speaker and can be powered by voltages as low as 3 V.
This circuit was found in an English documentation from 1969. The transistors are of the time,...
When establishing the voltage at the input of this regulator, the output voltage rises smoothly until...
To obtain an AND gate we have the configuration shown in the figure. With the values indicated for the...