What is Transistor analysis: Definition and 14 Discussions

The germanium alloy-junction transistor, or alloy transistor, was an early type of bipolar junction transistor, developed at General Electric and RCA in 1951 as an improvement over the earlier grown-junction transistor.
The usual construction of an alloy-junction transistor is a germanium crystal forming the base, with emitter and collector alloy beads fused on opposite sides. Indium and antimony were commonly used to form the alloy junctions on a bar of N-type germanium. The collector junction pellet would be about 50 mils (thousandths of an inch) in diameter, and the emitter pellet about 20 mils. The base region would be on the order of 1 mil (0.001 inches, 25 μm) thick. There were several types of improved alloy-junction transistors developed over the years that they were manufactured.
All types of alloy-junction transistors became obsolete in the early 1960s, with the introduction of the planar transistor which could be mass-produced easily while alloy-junction transistors had to be made individually. The first germanium planar transistors had much worse characteristics than alloy-junction germanium transistors of the period, but they cost much less, and the characteristics of planar transistors improved very rapidly, quickly exceeding those of all earlier germanium transistors.

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  1. altruan23

    Engineering Constant current source transistor circuit - differences between 2 types?

    So basically we can have a constant current but i don't understand this circuit. for example: i can have the Ia what ever I want with current divider rule: Ia = Iq * R2/R3. So Ia is proportional to the ratio of R2/R3. And if i give a resistor at the collector terminal, if i change it between...
  2. altruan23

    BJT emitter circuit weird equations?

    Summary:: So apparently the equations schould be correct but I am not sure about it. Isnt R1 = Ub(10V) - Base voltage / Iq + Ib --> Ub is the source voltage 10V. And schouldnt R2 be :base voltage / Iq?
  3. A

    Engineering Voltage gain for amplifier (JFET) in common gate

    First the hybrid model, I assume the capacitor works as a short circuit regarding the altern current: $$A_V=\frac{v_o}{v_i}$$ $$v_i=-v_{GS}$$ $$v_o=-i_LR_L$$ $$i_L=g_mv_{GS}+\frac{v_{DS}}{r_d}$$ Now I use the Kirchhoff's law to get $v_{DS}$. I consider this close loop: $$-v_i-v_{DS}+v_o=0$$...
  4. D

    Engineering Input and Output Impedance of circuit

    Hi, I have a circuit with 3 transistors I want to rewrite to a small signal model. When multiple transistors are in the circuit I get confused how to do it. This is the signal model and small signal model I have. Is it wrong?
  5. J

    Understanding the base emitter voltage in a common emitter NPN BJT

    ##V_{BE}## is basically the difference in voltage between the base terminal and the emitter terminal. Normally when silicon is used and the transistor is biased to operate in the active region, ##V_{BE}## = 0.7 V approximately. The way I understand this is that for an npn BJT, the applied...
  6. Peter Alexander

    Engineering Compute the voltage gain of this bipolar junction transistor circuit

    This is the given schematic. The result should be $$A_u = \frac{R_b g_{21}}{1 + R_b g_{22}} = -50$$ and the way I wanted to tackle this problem is by stating $$A_u = \frac{-R_b i_2}{u_1} = \frac{-R_b (g_{21} u_1 + g_{22} u_2)}{u_1} = \frac{-R_b (g_{21} u_1 + g_{22} u_2)}{g_{11} u_1 + g_{12} u_2}...
  7. Jayalk97

    Difference between h-parameters and hybrid pi?

    Hey guys, I'm confused as to the difference between the h-parameters usually given by datasheets and their hybrid-pi model analogues. For instance, I know hfe = Beta in small signal analysis, but what about the other h-parameters. Thanks for any help with clarifying this.
  8. Wrichik Basu

    B What is the utility of grounding in this Transistor case?

    I am attending an online lecture course on semiconductor physics. While explaining the common emitter mode of transistors, the professor sketched this diagram on the board: (I added something more to explain better) I understand that the emitter has to be at the same potential, and that is...
  9. Cocoleia

    BJT and MOSFET complete analysis

    Homework Statement I have been given the world's longest transistor problem as an assignment :wink: Here is the circuit: I am asked to find: a) V1, V2 and V3 using DC analysis b) AC equivalent circuit c) AC tension gain: Ava=Vx/Vsig d) AC tension gain: Avb=Vo/Vx e) Total AC tension gain...
  10. T

    Solving Op-Amp Current Analysis: LH0005 National Semiconductor

    Thank you for reading my post. I'm currently studying Op-amp, and there is a homework about LH 0005 of National Semiconductor for me to do: determine the collector current through each transistor I'm trying to find the IC2 but don't know how. Please help me with this :) Homework Statement...
  11. thegreengineer

    BJT transistor analysis: common emitter confusion

    Recently I started studying semiconductors and analogue electronics. First I studied the diode and its I-V characteristics and analysis in DC circuits, as well as in AC circuits. Now I started with BJT transistors. I was explained that transistors act as electronic switches. My problem is not...
  12. S

    Transistor analysis: find currents and voltages

    Homework Statement I’m having trouble with analysing the transistor circuit attached to find VC, VB, VE, IC, IB and IE. Homework Equations These equations are taken from a previous example VE = VBB – VBE IE = (VBB – VBE)/RE IB = IE/β+1 IC = β/(β+1) x IE VC = VCC – ICRC β=100...
  13. S

    Solving Transistor Analysis Homework: (\frac{W}{L})R_D=1.5 kΩ

    Homework Statement Just started learning about transistors, and I am having difficulty doing this problem. The transistor in the circuit has k_n ^'=0.5mA/V^2, V_t=0.5 V, \lambda =0. Show that operation at the edge of saturation is obtained when the following condition is satisfied...