Hi ! I' ve found this easy tutorial: link but I've still got a problem, according to what I think the RLO is 0V, so the lowest diode of bargraph will be the only one litted only at 0V, right ? So, I think I have to put in a resistor before the RLO, but what value of resistor should I use ? (yeah I'm newbie at electronics ) Thanks for any help, Greetz
Welcome to Bit-Tech, pascalek! Yes, your resistor is needed to raise the zero point. From this guide, For best accuracy, use a preset (trimmer) pot that covers the calculated resistor value.
Thanks cpemma, but as I said I'm a newbie. I want to make RLO around 5 Volts (cause that will be the lowest voltage in my LM317T fan controller). So will this be ok for R2: The shop selling them says they are precise, mounting, cermet. I think the best value would be 10k (also available are 1k, 2k, 5k, 50k and 100k). Am i right ?
The 10k is the one to go for. Assuming maximum output from the 317T is 10.5V, the full 10k will give a minimum at 11/20 x 10.5 = 5.8V, any adjustment will reduce the minimum so 5V min is easily set.
