This basic Schmitt trigger was found in an American publication from 1968. The circuit uses transistors from the time. Modern general-purpose types can be used.
Toshiba LDO Regulators Toshiba has a wide variety of low voltage drop (LDO) linear regulators...
This is the project found in a 1981 publication, but it is still viable. It is a simple AM...
This is the circuit of a commercial flash from the 60’s. The circuit was published by the march...