How to distinguish PNP transistor and NPN transistor

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Dispatch of net of machine tool of Chinese numerical control: NPN transistor - how to distinguish PNP transistor and NPN transistor indicate only not clear transistor dynatron, can judge its polarity with avometer, decide it is silicon canal or germanium canal, distribute its pin with time zone. Be in charge of to general small-power, when judgement general appropriate uses RX1K file.

Move is as follows: 1.

Measuring resistance of as aleatoric as what measure pen of will red black list to measure transistor instead bipod, the again red black crossing-over that express a pen still measures this bipod resistance, measure resistor reading twice to differ, we measure resistor reading that lesserly make be being measured, we measure resistor reading that more greatly make be measured instead. 2.

Decide 3 pin invent base general transistor on date 1.



Avometer makes 3 kinds measure, namely 1-2, 2-3, 3-1, cent is being measured and every kinds are measured instead again. In be being measured 6 times this, have 3 times belong to measuring, and resistor reading not identical. Find out measuring that pin with the greatest resistance, for example 1-2, another pin 3 it is base. Because be in charge of no matter,this is or canal, join reversely for two diode and become (like attached drawing) . Blast off extremely, between collector and base measuring resistance namely general diode to resistor, very small. When two watches the pen is received collector and blast off extremely when, its block value is ambitious at general diode to resistor. 3.

Pen of differentiate polarity black list accepts firm already base, red watch pen receives another meaning pole, if be,measuring, it is NPN canal, if be measured to turn over, it is PNP canal. Because black list pen receives the batteries inside avometer to be being carried,this is, if be,measuring, what black list pen receives is P end, transistor belongs to NPN model. If be measured to turn over, what black list pen receives is N end, transistor belongs to PNP model. 4.

Affirmatory collector and blast off extremely right collector and blast off extremely make measuring. When be being measured, what pen of black to NPN canal list receives is collector, to PNP canal, what black list pen receives is to blast off extremely. Because be being measured no matter,this is or measure instead, knot of a PN is in retrorse, batteries voltage descends on retrorse PN knot for the most part. Emissive knot is slanting, the electric current that when collect circuit slants instead, has flowed is bigger, the resistance that present is lesser. Be in charge of to NPN so, when collect, shoot when a resistor is lesser, what collector receives is batteries anode, what receive namely is black list pen. To PNP canal, when collect, shoot when the resistor between is lesser, blast off extremely those who receive is black list pen. 5.

Differentiate is silicon canal or germanium canal to blasting off extremely base is done measuring, be like deflexion of pressing with a finger 1/2- - 3/5, it is silicon canal. Be like deflexion of pressing with a finger 4/5 above, it is germanium canal. Because resistor is blocked,this is right base -- shoot extremely make when be being measured, add in base shooting the voltage between is Ube=(1-n/N)E, e=1.

5v is batteries voltage, the total branch squares formed by crossed lines that N is the some volts d.c. that has linear scale is counted, n is watch needle the number dividing case in the deflexion on this graduation mark. Normally silicon is in charge of U=0.


7v, germanium is in charge of Ube=0.


3v. Because this is when the test, to silicon canal, n/N is 1/2-3/5 about; To germanium canal, n/N is 4/5 above about. Additional, to the differentiate of general small-power, avometer is unfavorable use Rx10 or Rx1 to block. With 500 model avometer measures silicon canal to explain, this watch internal resistance is blocked in Rx10 is 100 Europe, be in charge of B to silicon.

E pole is made be being measured is, electric current amounts to IBE=(1.


7v)/100 Europe =8mA, ? The electric current when the canal that measure germanium is even big, block electric current with Rx1 bigger, possible attaint transistor. Block as to Rx1k, should block batteries voltage taller, have 1v commonly, 12v, 15v, 22.

5v a few kinds, pn knot breakdown is caused likely when be being measured instead, this blocks reason to also answer careful with. Using avometer of pressing with a finger to judge transistor very easily is NPN PNP model, with RX1K archives red watch pen receives pen of base black list additional and polar, if block is worth minor place,measure transistor to be Pnp model. If block value is the 2nd NPN letter that distributes homebred transistor model from model greatly relatively,be A, C is PNP transistor, if 3AX31 is PNP transistor 3BX5,B, D is NPN transistor it is NPN transistor, 3DD15 it is NPN transistor. Among them AB is germanium transistor CD is silicon transistor. CNC Milling