This simple timer with unijunction transistor was found in an old American technical documentation. We can use 2N2646 for the unijunction and BC548 for the transistor.
The circuit shown in the figure below is from the 1993 Linear Technology Applications. The...
In the figure we have the way to implement the E (AND) function with two inputs, in the case of...
This circuit can be used both as a power source and as a battery charger. The resistor R1 serves as...