Judging the pin position of the triode
Nov 02, 2019| Stay Charging Safely with SChitec
Judging the pin position of the triode
The pin position of the triode is judged, and the pin position of the triode has two package arrangements.
The triode is a junction-type resistor device. Its three pins have obvious resistance data. When testing (using a digital multimeter as an example, red pen +, pen--) we switch the test gear to the diode file (bee) Sound file)
The base resistance of the normal NPN structure transistor (B) to the collector (C), the emitter (E) has a forward resistance of 430 Ω to 680 Ω (depending on the model, the difference in magnification, this value is different) reverse The resistance is infinite; the base resistance of the normal PNP structure of the transistor (B) to the collector (C) and the emitter (E) is 430Ω-680Ω, and the forward resistance is infinite. In the case where the collector C does not bias current to the emitter E, the resistance is infinite. The base-to-collector test resistance is approximately equal to the base-to-emitter test resistance. Normally, the base-to-collector test resistance is about 5 to 100 Ω less than the base-to-emitter test resistance (high-power tube). More obvious), if this value is exceeded, the performance of this component has deteriorated, please do not use it again. If it is used incorrectly in the circuit, it may cause the working point of all or part of the circuit to deteriorate. This component may also be damaged soon. High-power circuits and high-frequency circuits react more obviously to such inferior components.
Although the package structure is different, it has the same function and performance as other types of tubes of the same parameters. Different package structures are only required for specific applications in circuit design.
It should be noted that some manufacturers produce some non-standard components. For example, the normal pin position of C945 is BCE, but some manufacturers have the EBC of this component, which will cause those careless workers to put new components in the undetected situation. The circuit is loaded underneath, causing the circuit to fail to work. In severe cases, the associated components, such as the switching power supply used on the TV set, are burned.
In our commonly used multimeter, test the pin arrangement diagram of the triode:
First assume a very "base" of the triode, connect the black pen to the hypothetical base, and then connect the red pen to the other two electrodes in turn, if the resistance measured twice is large (about a few K to tens K), or both small (hundreds to a few K), repeat the above measurement for the test pen. If the two resistance values are opposite (both small or large), then the assumed base is correct. Otherwise assume an extremely "base" and repeat the above test to determine the base.
When the base is determined, the black meter is connected to the base, and the red meter is connected to the other two poles. If the measured resistance is small, the transistor is NPN, and vice versa.
Judging collector C and emitter E, taking NPN as an example:
Connect the black test lead to the hypothetical collector C, the red test lead to the hypothetical emitter E, and pinch the B and C poles by hand, read the C and E resistance values shown in the header, and then reverse the red and black test leads. Retest. If the first resistance is smaller than the second, the original assumption is true.