-
MOSFET Astable: NP-BX1 Rundown
After eight months from a full charge, an old NP-BX1 lithium battery has come to this:

Astable green – NP-BX1 – 2.31 V The astable still ticks along at 1.4 seconds per blink, but the green LED barely lights up from a 2.1 V battery:

Astable green – NP-BX1 – 12 mV 100 ohm A pulse of 12 mV across the 100 Ω resistor puts the LED current at a mere 120 µA: no wonder the poor thing wasn’t visible in ordinary room light.
Another full charge restored its vigor for another couple of seasons.