Tagged Questions
-2
votes
3answers
180 views
How do I calculate the required value for a pull-down resistor in a PWM circuit?
I'm using 74HC595 with SoftPWM to control some LED's.
When the 74HC595 is off, its outputting about 0.57v, enough to turn my LED's on somewhat.
How do I work out the value of the pull-down resistor ...
4
votes
2answers
289 views
Small, cheap, and simple driver for 16 RGB LEDs
I am working on a board design that will put 16 RGB LEDs in a circle around a rotary encoder. I want this setup to be simple so that I can run it from any micro with limited software (ie. built in PWM ...
2
votes
1answer
498 views
Functional difference between various astable 555 circuits
Looking through some 555 square-wave-generator circuits (possibly with variable duty cycle for 4-wire PWM fan control) I've found three different circuits:
From the Wikipedia 555 article, a ...
9
votes
7answers
2k views
LEDs on a (battery) budget! – How can I lower the current through a LED without using up the battery?
EDIT: Here is a much brief version, the meandering motivated version is probably subsumed in the parent question on general battery life optimizations.
How can I lower the current into a LED ...
