This watch uses a liquid crystal display. The circuit is from the 80s and the module used is uncommon nowadays. Power is provided by a single cell.
This amplifier circuit with a low power MOSFET was found in Popular Electronics from the 90s. The...
The diagram shows a simple way to adjust a 7805 to have output voltages up to 12 V. The circuit is from...
With the circuit shown in the figure, we have a logic signal to activate a calling device when...