This circuit appeared in Amateur Radio Today in an issue and was found in a 1995 issue. The circuit is for the AM band up to 3 MHz. The transistors are general-purpose.
An advanced motor control software plug-in for Microchip’s MPLAB® X Integrated Development...
This relay without lock uses a general-purpose transistor. The relay is according to the supply....
This signal follower is from a 1970's documentation. So it uses the traditional configuration at the time...