On Sat, 08 Aug 2009 10:17:24 +0100, Jim Lesurf
wrote:

It is all too easy to make an amplifier that looks OK on a test bench
connected directly to a test load - then find it bursts into oscillation,
or its other properties alter - when given some other load. I've also seen
this happen when someone was using an oscilloscope that didn't reach the
oscillation frequency. So the audio waveform became distorted, but with no
visible sign of the RF bursts until they tried a faster scope.

There is a general rule in design that everything will oscillate. The
only consistent exception to this rule occurs when designing an
oscillator.

d