This circuit is a variation of the previous one, indicating a voltage range, for example 11.5 to 12.2 V for a red LED and a 10 V zener. The circuit is from an old English documentation.

This circuit is a variation of the previous one, indicating a voltage range, for example 11.5 to 12.2 V for a red LED and a 10 V zener. The circuit is from an old English documentation.