Instructables

time /magic fountain

could anyone help me with that time /magic fountain
http://www.instructables.com/id/The-Time-Fountain-Also-know-as-Magic-Fountain/

What do i have to do with this information "The transistor (2N1711) can handle a maximum current of 500 mA"?
could you also tell me wich potentiometer i should use and how i have to control the leds with them?

itge13 (author) 2 years ago
thank you mpilchfamily. for the 500ma could i use eg for 3v 20mA maximum 25 pcs? could you tell me a potentiometer that would work?
Assuming your power source is able to support up to 500mA then yes you can use 25 of those LEDs. But it would be best not to run the transistor at its max like that, so 20 may be best.

Once again the schematic calls for 2x 1 mega ohm pots. Any pot will do as long as its a 1 mega ohm pot. But if you want very fine control of the system then spend the extra money for a couple of 10 turn 1 mega ohm pots. A conventional pot will go from 0 to 1 mega ohm in a single turn . The 10 turn pots take a full 10 turns to reach its full resistance giving you more precise control over the settings.
itge13 (author)  mpilchfamily2 years ago
thank you a lot. that was very informative and helpful!
He mentions the limit of the transistor so you know how much current the circuit can handle. If you use too many LEDs then you will be drawing too much current through the circuit. He doesn't mention the number of LEDs to use cause it will vary based on what LEDs you use and how much current those LEDs draw.

As for the potentiometers he shows you in the schematic. You need 1 M ohm pots for the build.