![]() ![]() This way, the dynamo is never disconnected from the load and the Zener does not need to shunt any current except in the case of a connection failure. Instead, I decided that I could do away with a flashing front light and just flash the rear light. I'm sure there is an elegant solution out there that allows the energy to be recaptured rather than wasted, but I'm already running the rear red LED close to its maximum current. I don't have room to put a big heat sink on it so I finally gave up on trying to shunt the current and getting rid of the off cycle energy as heat. I got some advice about using a power transistor to shunt the current, but using a 20W transistor still resulted in the device getting too hot too fast. At a frequency of about 2 Hz and a duty cycle of about 50%, I didn't think this would be a problem, but the damn Zener hits 100☌ within a minute and showed no signs of slowing down, suggesting that I was taking it to within an inch of its life. ![]() While the standlight works well, the blinking circuit requires that a 5W Zener diode shunt all 500-600 mA of dynamo current during the off cycle of the flash. I've been tinkering with my dynamo powered LED flasher circuit recently. Jump to Attiny10 programming tutorial if you want to skip my long winded preamble.
0 Comments
Leave a Reply. |