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Ib= (12V-0.6V)/100K = 0.114mA
Ic= (10.6-.2)/2.2K = 4.72 mA
4.7ma will easily light an LED
current gain = Ic/Ib = 4.72mA/0.114mA = 41.46 easily within the HFE of common transistors.
Ken
Sorry Ken....4.7ma through an LED will not light it.
No matter what color the LED is.
15 to 30ma does the job.
Sorry but you're wrong, 4.7 mA will light an LED, although not very brightly, 30mA will also overheat some LEDs.
So, at what current is "on" for an LED. I frequently use, and see, status LEDs running at currents >10mA. I've used super bright LEDs for status indicators at 1ma on battery devices. Definately shows on or off status. Why waste power.I like my LED's to be driven properly. Either on or off. Not in "low power mode".
So, at what current is "on" for an LED. I frequently use, and see, status LEDs running at currents >10mA. I've used super bright LEDs for status indicators at 1ma on battery devices. Definately shows on or off status. Why waste power.
ken
No, it's not "bright". But it definitely shows an on/off status. I've also used low brightness as a status..."the LED works!", "these is power!"...high brightness then indicates a change in status.1ma. With a LED. And it is bright.