Filament source (T398E)

Despite being transistorized, this is a constant current source circuit for 1 V valve filaments such as the 1H4 tube.

Simple NiCad Charger (CB792E )
This charger can be used with one to four AA, AAA, C or D cells. The maximum current is given by R...
RIAA Amplifier (CB24004E)
Using an RCA CA3035 integrated circuit, this turntable circuit was found in the February 1970...
Shunt Regulator TL431 (CB14547E)
This circuit uses an unusual Motorola voltage reference. Other manufacturers also provide this...