Avometer differentiate dynatron the canal method that reachs pin

The canal of dynatron differentiate that reachs pin is a basic skill of electronic technology abecedarian, measure to help a reader master quickly sentence a method, writer summary gives 4 a pithy formula: “3 reverse, seek base; PN knot, calm canal; Arrange arrowhead, deflexion is big; Measure forbid, touch mouth. ” below let us undertake explanatory sentence by sentence.
One, 3 reverse, seek base
Everybody knows, dynatron is the semiconductor device that contains two PN form. According to two PN the knot joins means differs, can divide for the NPN dynatron with type of two kinds of PNP different electric conduction, the ohm that test dynatron wants to use avometer is blocked, choose R × 100 or R × 1k is blocked. Assume we do not know the dynatron that be measured is NPN model or PNP, also divide not clear each pin is what electrode. The first pace of the test is judgement which pin is base. At this moment, we allow to take two electrode (it is like these two electrode 1, 2) , with avometer two reverse that express a pen measure it, retrorse resistor, observation expresses the deflexion point of view of the needle; Then, reassume 1, two 3 electrode and 2, two 3 electrode, measure them topsy-turvy respectively, retrorse resistor, observation expresses the deflexion point of view of the needle. In be measured 3 times this topsy-turvy, have twice necessarily measure result close: The needle is expressed in be being measured topsy-turvy namely deflexion is big, deflexion is small; Remnant is to measure point of view of around finger deflexion topsy-turvy necessarily the next time very small, that pin that did not measure this is the base that we should search.
2, PN knot, calm canal
After the base that finds out dynatron, we are OK the electric kind that defines pipe according to base and additionally two square all along that PN writtens guarantee between electrode. the black list of avometer the pen contacts base, red watch pen contacts the either electrode in additionally two electrode, point of view of deflexion of finger of the head that be like a watch is very old, explain to be measured dynatron is NPN canal; Angle of deflexion of finger of the head that be like a watch is very small, be measured to be in charge of it is PNP namely model.
3, suitable arrowhead, deflexion is big
Found out base B, additionally two electrode which it is collector C, which be to blast off extremely E? At this moment we can decide with the method that measures ICEO of penetrable electric current collector C is mixed blast off extremely E. (1) to NPN dynatron, according to this principle, the pen of black, red watch that uses avometer is measured topsy-turvy polar between, retrorse resistor Rce and Rec, although be measured twice in angle of avometer finger deflexion is very small, but careful observation, always meet deflexion angle is once largish, right now voltaic flow direction is certainly: C of the black → that express a pen extremely → B extremely → E extremely pen of → red watch, the arrowhead direction in as it happens of voltaic flow direction and dynatron symbol is consistent (” suitable arrowhead ” ) , what right now so the black place that express a pen receives is collector C certainly, what the red place that express a pen receives is to blast off certainly extremely E. (2) to PNP model dynatron, the truth also is similar to NPN model, flow direction of its electric current is certainly: E of the black → that express a pen extremely → B extremely → C extremely pen of → red watch, flow direction of its electric current also agrees with the arrowhead direction in dynatron symbol, what right now so the black place that express a pen receives is to blast off certainly extremely E, what the red place that express a pen receives is collector C certainly.
4, do not measure piece, touch mouth
If be in ” suitable arrowhead, deflexion is big ” in measuring a process, if because put upside down twice of around,measure deflexion of pressing with a finger all too small when distinguishing hard, be about ” touch mouth ” . Specific means is: Be in ” suitable arrowhead, deflexion is big ” in be being measured twice, hold the combinative department of two watches pen and pin respectively with two hands, contain with mouth (or touch with the tongue) base electrode B, still use ” suitable arrowhead, deflexion is big ” differentiate method can distinguish collector C and blast off extremely E. The action of buy resistor slants to dc since human body among them, the purpose is to make the effect more apparent.