The circuit shown was found in American documentation from the 1990s. The transistor can be of any general-purpose type.
We found this circuit in the semiconductor ON manual using couplers of the time. These components...
Found in a 1967 RCA manual, this circuit uses components from the era that can be replaced by...
Linear Technology (www.linear.com) has in its component line the LT3518, recently launched, which...