This biestable vox circuit was found in an old documentation. The circuit makes use of components of the time (80's) and can work as a shield since the power is 5 V.
We found this preamplifier for recording heads in a 1980s documentation. The circuit can be used...
An advanced motor control software plug-in for Microchip’s MPLAB® X Integrated Development...
This circuit is from Delco Radio found in a 1968’s documentation. The transistors are of the time...