Motorcycle headlight monitor (CB9117E)

This simple circuit was found in Popular Electronics from the 1980s. The circuit uses an LED as an indicator.

15W Transistor Amplifier (CB1320E)
The circuit presented was found in a European publication of the 1980s. Used transistors are not...
TPS7A89 LDO Regulator with Energy Management
March 2017 - Mouser Electronics announces its new TPSA89 voltage regulator from Texas Instruments with...
Sharp Cut Filter (CB6732E)
Found in American documentation from 1968, this circuit has an acute cut-off of the frequency to...