Dimming leds with transistor and pot

496

06:20:06

As simple as it sounds. Just trying to get the ratios right before I throw everything together. Deets: 
28 LEDs, all probably 30mah max
Power source: usb plug
Target: led array for macro photography. (Also means no flickering pwm dimming)
Resources: scrap parts
If none of these work designs function within the next hour, im gonna slap a few 100ohm resistors on the input and call it a day. The goal is to get it done.

published 9 years ago

thebugger

9 years ago

Never power on an LED without a current limiting resistor. The transistor hFe may be quite higher than the one in the simulation, or due to thermal drift the hFe may rise to a point where the LED will burn out

rich11292000

9 years ago

Bugger he needs example.

thebugger

9 years ago

He should just add a series current limiting resistor to the LED

silitanyuk

9 years ago

yes

silitanyuk

9 years ago

yes

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