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Germanium Transistor musings

Discussion in 'Electronic Design' started by Tim Williams, Feb 6, 2006.

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  1. Tim Williams

    Tim Williams Guest

    I have a TO-3 size Tung-Sol 86X2 germanium transistor, removed from, I
    believe, a low voltage regulator circuit in an organ (transitional age: 6 x
    6CG7 master oscillators for the 12 individual notes, plus a lot of pairs of
    TO-5 germanium transistors for frequency division flip-flops to generate the
    lower octaves). Anyways, out of idle curiosity I hooked it up. Here's what
    I got.

    Type: PNP germanium power transistor, pins as indicated on underside
    case = collector).

    Maximum ratings:
    (Values at roughly 20-30°C. Values are absolute because I don't feel like
    writing negatives on every single parameter.)
    Vce = 22V (B open)
    Vcb = 30V (B, E grounded)
    (Zener type characteristic; no avalanche behavior noted.)
    Veb > 36V
    Maximum Ic, Ib unknown.

    Didn't measure leakage currents.
    Didn't measure capacitances.

    Operating Characteristics:
    Vc = 12V, Ic = 266mA, Ib = 1.7mA
    DC gain (beta) = 150 (200 at 50°C)
    Vce(sat) = 0.22V (Ib = 30mA, Ic = 1A)
    Vce(sat) <= 0.5V (Ib = 40mA, Ic = 2A)

    Switching Characteristics:
    (Square wave input, tr = tf = 50ns. Base resistor 47 ohms, collector load
    15 ohms, supply +15V, Ic ~= 1A when ON.)
    At beta = 10 (Ib(ON) = Ib(OFF) = 100mA):
    Delay time (from input rising edge to change in Ic), td = negligible
    Collector rise time, tr = 3.5us
    Storage time (from input falling edge to change in Ic), tstg = 1us
    Collector fall time, tf = 2.4us

    At beta = 100 (Ib = 10mA, Ic = 1A):
    td = negligible
    tr = 50us
    tstg = 4us
    tf = 12us

    Suprisingly, that's not too bad, at least at lower gain values. You could
    get what, 50 maybe 100kHz bandwidth from an amplifier using these! It would
    be guitar-player-friendly too. ;o) Other than that, you could make use of
    the more than doubled headroom and build low-frequency inverters to run on
    single cell PV setups for instance (such a circuit appeared in Electronics
    Now, with the author none other than Fred Nachbaur, of McTube fame).

  2. .
    [PNP Ge transistor characterization]
    So, what's the question? I just noticed the other day that in my parts bin
    I have 8X TIP33C, and almost 100X MPSA06. So what? ;-)

    Version: 3.1
    GAT(E P) dpu s: a++ [email protected] P+ L++>+ !E W+ N++ o? K? w-- !O !M !V PS+++
    PE Y+ PGP- t 5+++)-; X- R- tv+ b+ DI++++>+ D-? G e+$ h+ r-- z+
    ------END GEEK CODE BLOCK------
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