Transistor: (semiconductor discrete device)
Semiconductor discrete devices generally refer to semiconductor diodes, transistors and semiconductor special devices.
Characteristic parameters: (diode)
If forward DC current: It is defined as the current flowing in the low-resistance direction of the diode. For the rectifier, it is defined as low-resistance under specified usage conditions. The average value of the maximum operating current allowed to pass continuously in the load's forward half-wave rectifier circuit. For silicon switching tubes, it is specified as the maximum forward pulse current allowed to pass through the diode under rated power.
Ifm forward peak current: defined as the maximum forward pulse current allowed to pass through the diode under rated power.
Vf forward voltage drop: It is defined as the average voltage drop of the diode when it passes the rated current.
The maximum reverse working voltage: for silicon rectifiers, it is 2/3 of the breakdown voltage; for silicon stacks, it is specified as the maximum reverse voltage applied during normal operation in a forward-rotating half-wave resistive load circuit. towards the peak voltage value. For germanium detector tubes, the silicon switch tube is specified as the voltage value generated by the reverse current between the poles.
Breakdown voltage: For soft breakdown devices such as germanium detectors and switching tubes, it refers to the inter-electrode voltage value given a given reverse current. For hard breakdown rectifier switching tubes, It refers to the voltage peak when the reverse characteristic curve turns sharply.
Characteristic parameters: (transistor)
HFE*** emitter DC amplification coefficient: when the collector voltage and current are at specified values, the ratio of Ic to Ib.
Fhfe*** emitter cutoff frequency: defined as the frequency of 0.707 (ie 3db) when hfe drops to 1khz.
F0 characteristic frequency: When the frequency is high enough, hfe will decrease at a rate of 6db per frequency range, and ft is defined as the frequency at which hfe=1.
The collector current when the Icbo emitter is open circuit and the collector and base voltages are at specified values. The collector current of Iceo when the base is open and the collector and emitter voltages are at specified values. The maximum allowable current of the ICM collector.
The maximum allowable power dissipation of the PCM collector. VCBO emitter open circuit, collector, base breakdown voltage. VCEO base open circuit, collector, emitter breakdown voltage. VEBO open collector, transmitter, base breakdown voltage.
Temperature characteristics of transistors:
For diodes, when the forward current is constant, the forward voltage drop decreases with the increase of temperature. At room temperature, the temperature increases by 1C. The forward voltage drop is reduced by 2-2.5mv and the reverse leakage current changes exponentially with the temperature. When the temperature increases by 1C, the germanium tube increases by 10% and the silicon tube increases by 7%.
For transistors, the parameters most affected by temperature include: VBE, ICBO, HFE.
Among them, VBE changes linearly at a rate of -(2-2.5)mv/C , Iceo changes exponentially when the temperature is not very high, doubling every 9-10C increase. HEF increases by about 2% as the temperature increases by 1C. In short, when the temperature increases, the collector current will increase.
Model naming method of semiconductor discrete devices:
1 National standard naming method: (Quoted from GB249-74, 1975) Semiconductor devices are composed of 5 parts
No. Part: Use numbers to indicate the number of electrodes of the device. 2. Diode. 3. Transistor.
Part 2: Use Chinese Pinyin to indicate the material polarity of the device. Diode: A, N germanium material, B, P germanium material, C, N silicon material, D, P silicon material, Transistor: A, PNP germanium material, B, NPN germanium material, C, PNP silicon material, D, NPN silicon Materials, E, compound materials.
Part 3: Use Chinese Pinyin to indicate the type of device. P ordinary tube, V microwave tube, W voltage stabilizing tube, C parametric tube, Z rectifier tube, L rectifier stack, S tunnel tube, N damping tube, U photoelectric tube, X low frequency and low power, G high frequency and low power, D low frequency High power, A high frequency high power, T body effect tube, B avalanche tube, J step recovery tube, CS field effect tube, BT semiconductor special device, FH composite tube, PIN, PIN tube, JG laser tube.
Part 4: Use numbers to indicate the serial number of the device. Part 5: Use Chinese Pinyin to indicate the specification number.
The naming method of Japanese semiconductor devices:
Part 1: Use numbers to indicate the number of electrodes of the device, 0, photoelectric tube, 1 diode, 2 transistor. . .
Part 2: S: A mark registered with the Japan Electronics Industries Association (JEIA).
Part 3: Use letters to indicate the type of material: A, PNP high frequency, B, PNP low frequency, C, NPN high frequency, D, NPN low frequency, F, P controlled thyristor, G , N control thyristor, H, N base unijunction transistor, J, P-channel field effect transistor, K, N-channel field effect transistor, M, triac.
Part 4: The JEIA registration number of the device has the same performance, but products from different manufacturers can use the same number.
Part 5: A, B, C, indicates that the model is an improved model of the original model. In addition to the above basic symbols, some suffixes are sometimes attached, such as: M: indicating that the device complies with the relevant standards of the Japan Maritime Self-Defense Force Staff Department. N, (extra circle) complies with Japan Broadcasting Association standards. H, (extra circle) for Hitachi Communications, K, (extra circle) for Hitachi Communications, Z, (extra circle) for Panasonic Communications, G, (extra circle) for Toshiba Communications, S, (extra circle) for Sanyo Communications. The second letter of the suffix usually indicates the HEF binning mark.
The nomenclature of semiconductor devices in the United States:
The nomenclature of semiconductor devices in the United States is relatively confusing. Here is the nomenclature of discrete transistor devices stipulated by the Electronic Industry Association (EIA).
Part 1: Use symbols to indicate uses and categories, JAN, or J for military use. None, civilian use.
Part 2: Use numbers to indicate the number of PN junctions, 1, diode, 2, transistor. . . .
Part 3: Electronic Industries Association (EIA) registration mark, N
Part 4: Electronic Industries Association (EIA) registration serial number.
Part 5: Different grades of the same model, A, B, C...
Naming characteristics of American semiconductor devices:
1 In addition to the prefix, Most of the devices starting with 1N, 2N, and 3N are made in the United States or have U.S. patents.
2 The fourth part is just the registration serial number and has no other meaning, so the parameters of adjacent numbers may be very different.
3. Devices with consistent performance produced by different manufacturers use the same registration number, so they can be used universally.
The model naming method of European semiconductor discrete devices:
At present, there is no clear and unified model naming method in European countries, but most European countries generally use the International Electronics Federation The standard version of the model naming method for conductor discrete devices.
Part 1: Use letters to represent materials: A germanium material, B silicon material, C potassium arsenide, D indium antimonide, R composite material.
Part 2: Use letters to indicate types. A detector switch and mixing diode, B varactor diode, C low-frequency low-power triode, D low-frequency high-power triode, E tunnel diode, F high-frequency low-power triode, H magnetic diode, K open magnetic circuit Hall device, M Sealed magnetic circuit Hall device, P photosensitive device, Q light-emitting device, R small power thyristor, T high power thyristor, U high power switching tube, X multiplier diode, Y rectifier diode, Z Zener diode, L high Frequency high power tube, S low power switching tube
Part 3: Registration serial number of general semiconductor devices.
Part 4: Binning marks for devices of the same model.
Basic principles for transistor substitution:
Same type: including the following three points.
1 The materials are the same, that is, silicon tubes are replaced with silicon tubes, and germanium tubes are replaced with germanium tubes.
2 The polarity is the same, that is, NPN replaces NPN tube.
The three types are the same, that is, ordinary triodes are replaced by ordinary triodes. Field effect tube replacement field effect tube.
Similar characteristics: The main parameters of the replacement tube are similar to those of the original tube. General-purpose transistors can be replaced as long as the following main parameters are similar, PCM, ICM, VCEO, F0. Among the above parameters, it should be considered that the parameters of the replacement pipe are greater than or equal to the parameters of the original pipe. For special-purpose triodes, other corresponding parameters should also be considered, such as low-noise triodes, etc.
Similar appearance: The appearance of low-power tubes is similar. As long as the polarity of each electrode is clear, it can be replaced. The appearance of high-power tubes is quite different. It is best to choose tubes with the same package as the original. to meet and approach the original heat dissipation conditions.