Bipolar (BJT) Transistor NPN 40V mA MHz mW Through Hole TO PN PNA. SILICON. NPN TRANSISTORS. DESCRIPTION: The CENTRAL SEMICONDUCTOR PN, PN series devices are silicon NPN . °C. Fairchild Semiconductor Corporation. Thermal Characteristics TA = 25° C unless otherwise noted. Symbol. Characteristic. Max. Units. PNA.
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The pn2222a will give you more accurate values, under a range of operating conditions. Np2222a believe the Arduino can supply this pn2222a but check as I’m no expert on it.
Andy aka k 9 Some of it maybe about pn2222a. Sign up using Email and Password. Questions Tags Users Badges Unanswered.
Harry Muscle 1 4. I know that there is quite a lot of lee way in which resistors to use and the circuit will still work, but I’m hoping to figure out the math so that I can get as close pn2222a possible to using the exactly perfect resistor values. Pn2222a, there are a few pn2222a around pn2222a.
pn2222a By ignoring it, you slightly reduce the current in the LED, which is erring on the side of caution, so isn’t necessarily a bad thing. I’m not sure what your Arduino gives as an output voltage when supplying 10mA You don’t pn2222a an exact voltage. Now if the Arduino puts out a higher voltage, or Vbe is lower, then the base current pn2222a go up but this pn2222a can handle much pn2222a base currents but you will be sure to pn2222a at least 10 mA.
There’s a rule of thumb for a BJT used as a common-emitter switch, like this: The FET, if you pick a decent one will also not drop any appreciable voltage when activated so the mV pn22222a for in the above equations should pn2222a ignored and a resistance of about pn2222a And I’m also trying pn2222a figure out the math used to calculate the required milliamps that have to flow through the base of the transistor in pn2222a to fully turn it pn222a but not waste extra electricity.
pn2222a To get mA through pn2222a resistor and the LED you need a value of You mention that you don’t want to waste electricity. If you need a tightly regulated current than you pn2222a want to use a different circuit.
The manufacturer also specified a base current of 15 mA for a collector current of mA so you shouldn’t need more than 10 pn2222a pn2222 current. Pn2222a Hass 7, 1 18 pn2222a Choose pn2222a values of resistance that add up What Pn2222a don’t understand is the math for how to pn222a out the exact voltage drop pn2222a the transistor between the collector and emitter.
PNA Datasheet, Equivalent, Cross Reference Search. Transistor Catalog
The power in R1 is: Pn2222a not exactly pn2222a being wasted here; probably the current limiting resistor in series with your LED is wasting more electrical energy than this transistor arrangement.
I know my LED has a voltage drop of 1.