This 1988 circuit makes a back-and-forth of LEDs whose speed is controlled by P1. All components used are common and the circuit can be powered by voltages from 6 to 9 V.
This receiver is from European documentation from the 90s. The integrated circuit is uncommon, and the coil...
With the circuit shown it is possible to measure capacitances and inductances using an ordinary...
This circuit was obtained in an old US 1974 documentation when Nixie tube displays were common. The...