Identification and detection of semiconductor triode
Identification and detection of semiconductor triode.
The triode transistor, also called a semiconductor triode,also called a bipolar transistor and a crystal triode,is a semiconductor device using current to control the current.Its function is to enlarge the weak signal into a large amplitude electrical signal and also be used as a contactless switch.
Classification of triode
According to the material: silicon tube, germanium tube.
according to the structure: NPN, PNP.
According to the function:switch tube,power tube,Darlington tube,photosensitive tube, etc.
According to power: small power transistor, medium power transistor, high power transistor. _Accordingto the working frequency: low-frequency tube, high-frequency tube, overfrequency tube. In accordance with the structure and process, the alloy tube and the flat tube.
According to the installation mode: plug-in transistor, patch transistor.
Detection of three and triode
Pointer type multimeter test triode
Detection of common triode by pointer multimeter
When using the pointer multimeter to determine the three electrodes, polarity and good or bad of the common triode, choose RX100 or RXlk gear.
Three upside down, look for the base: with a black pen to connect a foot (assuming it is B pole), the red pen is connected to the other two feet respectively, and two resistance values are measured, both are larger or smaller; the change of the pen, the red pen to connect the foot, the black pen respectively to the other two feet, measured two electrical values, are smaller or larger (Note: two measurements knots. The opposite is the result. It indicates that the transistor is good and the assumed pin is the base.
PN junction,fixed pole type:black surface brush contact base,red surface brush contact with the other two poles,the multimeter is indicated as low resistance,then the tube is NPN; on the other hand,the multimeter indicates a high resistance,then the tube is PNP.
The internal equivalent diagram of the transistor is shown in Figure,When measuring,it is necessary to keep thinking about this diagram so as to achieve practice.
Judge the collector and emitter along the arrow,deflect large;Uncertain,move the mouth.Put the pointer type multimeter ohm in "RX100" or "RX1k",take the NPN tube as an example,connect the black pen on the hypothetical collector C.The red pen receives the hypothetical emitter E,and holds the B and C poles with hands (no direct contact between B and C),and passes the bias resistance between the B and C through the human body, equivalent to the B,C,and readout the watch head.The resistance of the two pens is then re measured,as shown in Figures 1, 2, 4.If the first measured resistance is smaller than the second time,the original hypothesis is established.
Detect the beta value with the hFE stopper of multimeter:Dial multimeter to hFE gear.The three pins of C,B and E of the transistors are inserted into the corresponding sockets,and the current amplification factor (beta) of the tube is read out from the meter.