The integrated circuit used in this regulator is not common today. The circuit is from a technical documentation from the 80's and is only used as a reference for eventual repair.
This circuit is from a 2004 documentation serving for signals from 1 MHz to 160 MHz. The antenna is...
This filter of two transistors has the cutoff frequency determined by the formulas next to the...
This Philips commercial circuit is from the 90's documentation. The integrated circuit must be...