Latching relay (CB25722E)

The figure shows how to connect a relay to obtain the latch effect. The circuit is from an Electronics Now from June 1994.

Variable zener diode (CB9969E)
In the figure we have the way to implement a 5 to 45 V zener diode with 50 mA of maximum current...
Wattmeter (CB23581E)
This circuit is from a Radio Electronics magazine from December 1958. The indicator instrument is analog...
12 or 24 W amplifier TDA1516Q or TDA1518Q (CB15980E)
These integrated ones consist of class B amplifiers with gain fixed 24 internally for better...