Low-Power Joule Thief Night Light

2017-02-19 by rincewind

The classic Joule-Thief circuit can be modified to work in a low-power burst mode: The base resistor R4 is increased to a value that provides just enough base current for startup. After startup, the base current is provided by C1 and transformer L1-L2. Each cycle, the B-E diode of Q1 charges C1 a bit, until[…] Read More…