The basic engineering rule when designing amplifiers is not to use too much gain in a single stage. A bipolar junction transistor (BJT) can provide the current gain but when considered during amplifications it requires more amount of current gain. The only issue I see with darlington is the gain will be too big for your application, so the circuit may oscillate, will be too sensitive and unstable, or even the noise from your mic will saturate your transistor. High DC Current Gain (hFE), typically 1000 Continuous Collector current (IC) is 5A Collector-Emitter voltage (VCE) is 100 V Collector-Base voltage (VCB) is. But it will be something like 4-10Megaohms. Also the MJ11015 is a PNP device wheras the 2N devices you mention are NPN. So based on the required output collector's DC voltage 2.5V, the required current through the collector's resistor, and the gain of your transistor (which based on the datasheet is 5000 at similar conditions) as well as on the fact the base is biased from collector, I can calculate the base current required to get 2.5V at collector - that will be achieved with ~4.7Megaohm.īecause the transistor's parameters may vary widely you have to elaborate the base-collector resistor such you get 2.5V on the collector. It doesnt quite work like that The Darlington is an arrangement of two transistors to make what appears as a single transistor with extremely high gain. Current directions and voltage polarities for npn (a.

C B E IE IC IB V CE VCE + +-(a) npn transistor C B E IE IC IB VCE VBE +-+ (b) pnp transistor Figure 4. The direction of the currents and the voltage polarities for the npn and the pnp BJTs are shown on Figure 4. The Darlington pair creates a super beta transistor. For the transistors of interest 100 which corresponds to 0.99 and ICE I. I know it because I know how the operating point of a normal or darligton transistor is calculated (and I did it in past). Product Name: Darlington Transistors Model: 10 Type: NPN-(TIP31C,TIP41C,TIP120,TIP121,TIP122),PNP-(TIP32C,TIP42C,TIP125,TIP126,TIP127 ) RoHS Compliant. Also called a Darlington configuration, emitter followers have a gain of unity. Btw how do u know it will work with this resistor? More items related to this product 10 x MPSA13 Plastic TO92 Extremely High Gain Current NPN Darlington Transistor 0.5A 30V NPN Darlington Pair Transistor.

Set gain of npn darlington transistor