Motorcycle headlight monitor (CB9117E)

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

Demonstration Microchip Boards of Consumer Monitors MCP39F511
July 2017 - Microchip's new MCP39F511 demonstration and development boards, which consist of...
Dual temperature and level control (CB9474E)
This circuit, which controls both the temperature and the level of a liquid in a reservoir, was...
LED Constant Current Source (CB12062E)
This circuit provides a constant current of 1 mA, stabilized by an LED, which can be equivalent to that...