The resistance between 2E and C
The resistance between 2E and C.Silicon tube is almost infinite size power pin tube in the tens of thousands of euros,high-power wrong tube in the hundreds of Europe.If the measured resistance is zero,it is explained that the internal short circuit of the transistor,when measuring the reverse resistance of the body tube or the resistance between E and C,will be extended with the time of measurement,the resistance is gradually reduced,indicating that the performance of the transistor is not stable.The reverse resistance between 3B.the silicon tube approaches infinity,and the germanium tube is above several hundred thousand euros.If the measured resistance is too small,it indicates that the transistor performance is not good;zero Europe indicates that the transistor is short-circuited.
Estimating the penetration current Iceo 1 Measurement of small power transistor RX1002 block,if it is PNP type tube,black stylus ( positive electrode in the table ) connected to E,the red stylus ( the negative pole in the table ) is connected to C.if it is a small power germanium tube,resistance in the tens of thousands of euros or more.If the resistance is too small,the needle moves slowly to low resistance,indicating that Iceo is big.
measurement power transistor RX10K2 block, if it is NPN type tube,red pen and E,black pen and C,at this time the measured resistance should be in the thousands of euros.If it is too small,it means that Iceo is too big;if it is infinite,the inside of the transistor is open.Then the meter is measured,and the meter needle should be infinite.If the stylus swings,the transistor Iceo is slightly larger.If the positive and negative values are equal,it indicates that Iceo is very large and can hardly be used.
The measured value 1 is measured with a multimeter hF,and the three pins of the transistor are respectively inserted into three holes of the hFe block,and the reading of the meter needle is the magnification of the transistor.The high power tube can be measured after the pin is connected to the line.2 multimeter without hFe block,can be measured by the following methods.Test the PNP type tube,the red pen and C,the black pen and E,with a resistance of about 100 k2 are connected between B and C ( with wet hands between B and C can be ),at this point the needle will be biased towards the low resistance side.The greater the amplitude of the needle swing,the higher the transistor value.New street test NPN type tube,red pen and E,black pen and C,other methods as above.If the resistance between B and C is connected,the stylus becomes smaller,indicating that the transistor value is not stable.
It is the most accurate method to judge the high frequency tube and low frequency tube according to the model of the transistor,and the multimeter can be estimated when the model is not clear measurement.RX1k2 is used to block the reverse resistance between B and E,and if it is above several hundred thousand, you will dial the table to RX10kQ,if the needle can be deflected to about 1 / 2 of the dial,it is shown that the transistor is a high frequency silicon tube.If the RX10k2 blocking value changes very little,it indicates that the transistor is a low frequency tube.