This is a 1946 post-war model radio. The 3-tube receiver has a long-known tube configuration.
This circuit from a Radio Electronics from February 1966 uses an LDR as a sensor. The transistor is a...
March 2017 - Texas Instruments LM5166 Synchronized Buck Converters are available at Mouser for 3V...
This is one of the possible triac power control configurations using as a trigger element a...