|
Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
|
Thread Tools |
28th Mar 2018, 9:26 am | #21 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,951
|
Re: Static damage to semi conductors
Static can certainly cause damage to RF devices - as mentioned, the device will contunue to behave as a transistor under DC conditions but noise-figure and gain at a few hundred MHz can be significantly worsened.
Early masthead preamps of a certain type sold in the early/mid01970s to the 70cm-band amateur market which used a grounded-base silicon bipolar transistor of a type more common in two-way-radio gear were prone to this if fed from an antenna that was not DC-grounded; hot, dry winds would build up a static charge. When your "10dB gain, 2dB noise-figure" preamp turns into one with 2dB gain and 10dB noise-figure you know you've got problems. I found the 'failed' transistors still worked as well as something like a BC108 in simple DC otr audio circuits! |