This is just comment, there is no question to be answered, but further comments are welcome.
I was working with an LED (uk.farnell.com/1716701) on stripboard, and lighting the LED at extremely low duty cycles, just while testing. I was finding that the LED was glowing a bit when it was supposed to be off.
I soon realised that the brightness depended on how I was holding the board. The LED was lighting visibly with the leakage current through my fingers. I tested another one and it is clearly visible at 2 µA.
It's standard practice to put a resistor from base to emitter of a transistor to make sure that it doesn't turn on from leakage current. A 10 kΩ resistor in parallel fixed the problem, and I'll include one in future where there could be confussion.
I was working with an LED (uk.farnell.com/1716701) on stripboard, and lighting the LED at extremely low duty cycles, just while testing. I was finding that the LED was glowing a bit when it was supposed to be off.
I soon realised that the brightness depended on how I was holding the board. The LED was lighting visibly with the leakage current through my fingers. I tested another one and it is clearly visible at 2 µA.
It's standard practice to put a resistor from base to emitter of a transistor to make sure that it doesn't turn on from leakage current. A 10 kΩ resistor in parallel fixed the problem, and I'll include one in future where there could be confussion.