This modulator circuit for low intensity signals is from old documentation. The integrated circuit used is uncommon today. The circuit operates with signals up to 2MHz.
In the figure we have a simple amplifier stage for BC547 series transistors. The gain is...
Found in a 1980s American documentation, this circuit can use a SCR and a general-purpose transistor....
This circuit was found in a 1973 publication. The operational ones can be exchanged for...