I recently decided to undertake a small project to convert a very high quality headlamp which uses an incandescent bulb to an LED one. While opening it up I discovered that it contains a Zener (bzx55c3v9 a 3.3v 500mw) in series with the 4 1.5v batteries (cells) and a 3.5v 2A incandescent bulb. Zeners are not used often and I am far from an expert but I do know that they have a breakdown voltage which when the input voltage rises above this voltage they begin to conduct and reverse the current back into a resistor. The explanation is from memory. The order of parts are Bulb-cell-cell-zener-cell-cell-switch-(back to bulb). Theoretically (in my mind) it would be like placing a battery in backwards which causes problems.
I am mainly confused as I have never seen them used in this way (without being in a voltage divider with a resistor) and can not find any mention of them being used like this. What bit of obvious information am I missing?
Thank you
I am mainly confused as I have never seen them used in this way (without being in a voltage divider with a resistor) and can not find any mention of them being used like this. What bit of obvious information am I missing?
Thank you