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  • Old germanium transistors.

    From albert@spenarnc.xs4all.nl@21:1/5 to All on Wed Mar 6 12:52:14 2024
    I have old germanium transistor from computers that were dumped
    in the 70's.
    The Hfe varies between 50 to 150.
    The Vbe varies between 110 and 230.

    A couple of these have a short between collector and emittor,
    below 1 ohm.
    (The intention was to make an oscillator under 1 V. The reference
    I got from this group were sine oscillators. The circuit that I
    are going to try is a blocking oscillator that hopefully
    convert 1 to 6/7 volts to replace a 9V battery.)
    --
    Don't praise the day before the evening. One swallow doesn't make spring.
    You must not say "hey" before you have crossed the bridge. Don't sell the
    hide of the bear until you shot it. Better one bird in the hand than ten in
    the air. First gain is a cat purring. - the Wise from Antrim -

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  • From Cursitor Doom@21:1/5 to albert@spenarnc.xs4all.nl on Wed Mar 6 21:58:57 2024
    On Wed, 06 Mar 2024 12:52:14 +0100, albert@spenarnc.xs4all.nl wrote:

    I have old germanium transistor from computers that were dumped
    in the 70's.
    The Hfe varies between 50 to 150.
    The Vbe varies between 110 and 230.

    A couple of these have a short between collector and emittor,
    below 1 ohm.
    (The intention was to make an oscillator under 1 V. The reference
    I got from this group were sine oscillators. The circuit that I
    are going to try is a blocking oscillator that hopefully
    convert 1 to 6/7 volts to replace a 9V battery.)

    Those shorts can be cleared by a high voltage pulse of short duration.
    Charge up a 1uF cap to 500V and apply it across the relevant terminals
    or between the case and the relevant terminal. You probably have tin
    whiskers and zapping them in this way is the most effective way of
    dealing with it.

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    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jeroen Belleman@21:1/5 to Cursitor Doom on Wed Mar 6 23:22:13 2024
    On 3/6/24 22:58, Cursitor Doom wrote:
    On Wed, 06 Mar 2024 12:52:14 +0100, albert@spenarnc.xs4all.nl wrote:

    I have old germanium transistor from computers that were dumped
    in the 70's.
    The Hfe varies between 50 to 150.
    The Vbe varies between 110 and 230.

    A couple of these have a short between collector and emittor,
    below 1 ohm.
    (The intention was to make an oscillator under 1 V. The reference
    I got from this group were sine oscillators. The circuit that I
    are going to try is a blocking oscillator that hopefully
    convert 1 to 6/7 volts to replace a 9V battery.)

    Those shorts can be cleared by a high voltage pulse of short duration.
    Charge up a 1uF cap to 500V and apply it across the relevant terminals
    or between the case and the relevant terminal. You probably have tin
    whiskers and zapping them in this way is the most effective way of
    dealing with it.

    I'd be surprised if you could bring Ge transistors back to life
    by such treatment. Sure, you'll blow the whiskers, but the
    transistor goes with it.

    Jeroen Belleman

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  • From Phil Hobbs@21:1/5 to Cursitor Doom on Wed Mar 6 17:38:59 2024
    On 2024-03-06 16:58, Cursitor Doom wrote:
    On Wed, 06 Mar 2024 12:52:14 +0100, albert@spenarnc.xs4all.nl wrote:

    I have old germanium transistor from computers that were dumped
    in the 70's.
    The Hfe varies between 50 to 150.
    The Vbe varies between 110 and 230.

    A couple of these have a short between collector and emittor,
    below 1 ohm.
    (The intention was to make an oscillator under 1 V. The reference
    I got from this group were sine oscillators. The circuit that I
    are going to try is a blocking oscillator that hopefully
    convert 1 to 6/7 volts to replace a 9V battery.)

    Those shorts can be cleared by a high voltage pulse of short duration.
    Charge up a 1uF cap to 500V and apply it across the relevant terminals
    or between the case and the relevant terminal. You probably have tin
    whiskers and zapping them in this way is the most effective way of
    dealing with it.

    A microfarad at 500V is 125 mJ. That'll blow a crater in the active device.

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

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  • From Cursitor Doom@21:1/5 to pcdhSpamMeSenseless@electrooptical. on Wed Mar 6 23:25:21 2024
    On Wed, 6 Mar 2024 17:38:59 -0500, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    On 2024-03-06 16:58, Cursitor Doom wrote:
    On Wed, 06 Mar 2024 12:52:14 +0100, albert@spenarnc.xs4all.nl wrote:

    I have old germanium transistor from computers that were dumped
    in the 70's.
    The Hfe varies between 50 to 150.
    The Vbe varies between 110 and 230.

    A couple of these have a short between collector and emittor,
    below 1 ohm.
    (The intention was to make an oscillator under 1 V. The reference
    I got from this group were sine oscillators. The circuit that I
    are going to try is a blocking oscillator that hopefully
    convert 1 to 6/7 volts to replace a 9V battery.)

    Those shorts can be cleared by a high voltage pulse of short duration.
    Charge up a 1uF cap to 500V and apply it across the relevant terminals
    or between the case and the relevant terminal. You probably have tin
    whiskers and zapping them in this way is the most effective way of
    dealing with it.

    A microfarad at 500V is 125 mJ. That'll blow a crater in the active device.

    Cheers

    Phil Hobbs

    Must be 0.1uF then. Or 0.01. There's bound to be someone on YT that's
    done it.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to All on Wed Mar 6 23:47:25 2024
    On Wed, 06 Mar 2024 23:25:21 +0000, Cursitor Doom <cd@notformail.com>
    wrote:

    On Wed, 6 Mar 2024 17:38:59 -0500, Phil Hobbs ><pcdhSpamMeSenseless@electrooptical.net> wrote:

    On 2024-03-06 16:58, Cursitor Doom wrote:
    On Wed, 06 Mar 2024 12:52:14 +0100, albert@spenarnc.xs4all.nl wrote:

    I have old germanium transistor from computers that were dumped
    in the 70's.
    The Hfe varies between 50 to 150.
    The Vbe varies between 110 and 230.

    A couple of these have a short between collector and emittor,
    below 1 ohm.
    (The intention was to make an oscillator under 1 V. The reference
    I got from this group were sine oscillators. The circuit that I
    are going to try is a blocking oscillator that hopefully
    convert 1 to 6/7 volts to replace a 9V battery.)

    Those shorts can be cleared by a high voltage pulse of short duration.
    Charge up a 1uF cap to 500V and apply it across the relevant terminals
    or between the case and the relevant terminal. You probably have tin
    whiskers and zapping them in this way is the most effective way of
    dealing with it.

    A microfarad at 500V is 125 mJ. That'll blow a crater in the active device. >>
    Cheers

    Phil Hobbs

    Must be 0.1uF then. Or 0.01. There's bound to be someone on YT that's
    done it.

    .... and wouldn't you know it - there is! This fellow uses 1000V,
    though:

    https://www.youtube.com/watch?v=xFwDXIYgBvQ

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