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What is the base current of a 2N3904 transistor?
With a base current of 20mA, that’s a collector current of way more than the 2N3904 can handle, so 20mA will saturate it thoroughly. You can probably get by with a lower base current. Look at a 2N3904 datasheet for gain at different collector currents.
What do you need to know about 3904 transistors?
Here is a link that shows various package sizes for 3904 transistors. Figure 2: 2N3904 circuit example – drawn in Scheme-it®. Since the 2N3904 is an NPN transistor, that means the base needs positive biasing (appropriate voltage levels and resistance) to turn on the collector emitter junction for proper current flow.
What is the Digi key part number 2N3904?
Figure 1: An illustration of the pin out of a standard TO-92 package for Digi-Key part number 2N3904FS-ND: E = Emitter, B = Base, C = Collector. Figure 2 shows a circuit example which turns on the collector emitter junction by energizing the base or biasing the transistor to turn it on by bringing 5 volts to the base via a slide switch.
What do you need to know about NPN transistors?
Since the 2N3904 is an NPN transistor, that means the base needs positive biasing (appropriate voltage levels and resistance) to turn on the collector emitter junction for proper current flow. Use of a load resistor (R1 above) is also important so there is not too much current being driven through the LED and transistor.
When does 2N3904 change from reverse biased to forward biased?
In normal state, 2N3904 acts as reverse biased and there’s no conduction between Collector & Emitter. When small voltage applies at its Base Terminal (normally 5V), 2N3904 converts its state from reverse to forward biased and conventional current starts flowing from Collector to Emitter.
What kind of resistor to base do I Need?
If you want less current thru the base, use a more capable transistor like a 2N2222 / PN2222. Hfe is just an empirical number it realy means nothing unless it is specificaly related to the Ibe and IC. For a 100 ma ic the 2n3904 is basicaly into the saturation region.
What kind of resistor do I need for a 3904?
The maximum current a 3904 can handle is 100ma, so is it okay too choose a resistor for a 100ma current so anything I hook up will work as long as it takes less than 100ma? I was poking around and found that there is a voltage drop of about .6v. So say if the transistor has a gain of 50 (not sure what the 3904 has), and I want 100ma.