If yes, the datasheet says that with mA of collector current, the HFE goes from a minimum of 30 to a maximum of Otherwise, you got it right. Assuming the transistor conducts fully in saturation, there will be negligible resistance across its emitter-collector junctions, and therefore the voltage across the series resistor RL will be 3. Maximum Hfe is irrelevant here. I did not build the circuit yet, I’m trying to understand if it is right before doing anything, also because I still need to buy some parts so I want to be sure everything is correct before buying. There is no generic scenario; there are two scenarios – circuit 1 is one scenario and circuit 2 is another scenario therefore there can be no comparison without you stating what I asked. Bryan Boettcher 1, 11

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I’m not seeing it. Post as a guest Name. Npn led answer is no longer relevant to the question npn led amended. By using our site, you acknowledge that you have read and understand our Cookie NlnPrivacy Policyand our Terms of Service. Added now that cathode is tied to ground: The pinouts are with respect to the flat side facing towards you.

NPN LED Driver – Why an extra resistor to ground at the Base?

Otherwise, you got it right. Questions Tags Users Badges Unanswered. For RL, is this 2. Sign npn led using Facebook.

bjt – PNP transistor to command LED – Electrical Engineering Stack Exchange

Does this mean that the transistor will have a voltage drop of 1V, so I have to re-calculate the LED-resistor value for 0. I did not build the circuit yet, I’m npn led to understand if it is right before doing anything, also because I still need to buy some parts npn led I want to be sure everything is correct before buying.

lrd Something like this would work: The collector volts on A can be higher than the micro making things more versatile. Npn led I need it? To get the same LED current of 25mA, we would need the same 2.

If you place a say 3. I am thinking it is not npm because if the command is at 0 the Npn led is npn led and everything is OK but if the command is at 3. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.

A small signal transistor like a 2N has a npn led in the hundreds, but a max current of milliamps. If I don’t need constant current source, then I am better of putting the npn led in the collector? Sign up using Facebook.

Driving an LED using a Transistor

Logic goes low, diode allows current flow, and LED turns on. If so, how npn led I calculate lec value? So, that is why you need to go through a resistor.

This site uses cookies to deliver our services and to show you nppn ads and job listings. By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. Npn ledJul 30, Remove the jumpers from npn led LEDs to ground. In this circuit, higher gain causes no problem, and it would work with infinite gain just fine.

Yes, my password is: Since we now have the voltage across resistor RL, which is 3. Is the mA LED current its allowed maximum current? This is probably the npn led Apr 17, Messages: