transistor failures

[thomas]

We have a remote outdoor sensor that is prone to failure (nearby lightning
we suspect). It is only a couple transistors (2N3904, 2N3906), a couple
100V electrolytic and ceramic caps, a1N4148 and a few resistors.
Unfortunately they are potted so I can't do a post-mortum. I can't use TVS
or similar that shorts when failed because it will load the controller,
which I can't modify.

Are there tougher transistors or other components that we can use?

 

[John Schuch1]

thomas wrote:

We have a remote outdoor sensor that is prone to failure (nearby lightning
we suspect).
--<snip>--
Are there tougher transistors or other components that we can use?
--<snip>--

What is the sensor sensing?
How long is the wire run from the sensor to the control?
How is it actually run?
What kind of wire is used?

John

 

[thomas]

Induction sensor
The Belden 8723 wire is 2TP 22AWG and a run can 100+ feet long, in metal
conduit.
12V is run on one pair with signal on the other.


"John Schuch1" <news@esdres.com> wrote in message
news:_sOQc.10857$9Y6.2722@newsread1.news.pas.earthlink.net...

thomas wrote:

We have a remote outdoor sensor that is prone to failure (nearby
lightning
we suspect).
--<snip>--
Are there tougher transistors or other components that we can use?
--<snip>--

What is the sensor sensing?
How long is the wire run from the sensor to the control?
How is it actually run?
What kind of wire is used?

John

 

[Watson A.Name - \"Watt Su]

"thomas" <none@yahoo.com> wrote in message
news:LrTQc.10673$n7.5578@fe37.usenetserver.com...

Induction sensor
The Belden 8723 wire is 2TP 22AWG and a run can 100+ feet long, in
metal
conduit. 12V is run on one pair with signal on the other.

You can put reverse biased diodes across some points to clamp the
voltages to the supply and ground. Zeners also might help in certain
places. When all else fails, use sockets so that you can replace the
parts that burn out. ;-)

And make sure that the diodes can handle high enough current to not burn
out, too.

"John Schuch1" <news@esdres.com> wrote in message
news:_sOQc.10857$9Y6.2722@newsread1.news.pas.earthlink.net...
thomas wrote:

We have a remote outdoor sensor that is prone to failure (nearby
lightning
we suspect).
--<snip>--
Are there tougher transistors or other components that we can use?
--<snip>--

What is the sensor sensing?
How long is the wire run from the sensor to the control?
How is it actually run?
What kind of wire is used?

John