So yesterday Mr Jiggles became a little oscillator - but rather than a balanced sine wave we had a light distortion where the upper half was a bit wider and the lower half was a bit narrower.
I usually like to check the ground potential relative to the output if there is a problem, but this one is fine - maybe it could use a cap across the the supply but nothing to explain the distortion.
Just for kicks let's look at the power coming into the collector at the same time as the oscillator state. Lots to learn from this one... The first thing that jumps out is that our output is a balanced cyclic form but the voltage looks like two different curves. If you haven't guessed, the reason is the led (remember there is a minimum voltage before it conducts and until we hit that voltage on the emitter not a lot gets to flow) - caps cover the transition interval. We could just leave out the led and only have a resistor to limit the current but since we can't always have things linear in real life I'm leaving it in - for character.
Other fun things to do are to tap from the collector or the emitter, to put resistor dividers in line to change the output voltage range, to bias the base to change the operating point of the transistor... lots of things.. endless things...
Anyway, every once in a while I like to just play around a bit and get a feel for how things actually work and see the changes in reality... touch a few wires to see which is sensitive to noise and how that propagates... troubleshoot the unexpected behaviors... see what happens when the loads match and when they don't... it's silly and pointless, but fun.