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Shake to start.
Just a heads up on the simplest form of current amplifier one can make.
This type of circuit is usually used in buffer stages where a current driver is needed, and usually has a very high frequency response due to the lack of Miller capacitance. This Miller capacitance is usually present in small quantities, however is often neglected, as collector variations usually don't interfere with the output of an emitter follower. In retrospect, the Miller capacitance in common emitter circuits is multiplied by the transistor's gain and decreses the high frequency response of the transistor to well below its self oscillation frequency.
However, due to the lack of this miller capacitance or more accurately the Miller Effect on the output and the very high bandwidth the emitter follower has, it is very prone to self-oscillations even in the most simple configurations.
You can see here that due to parasitic capacitances and inductances in a real BJT model, even the simplest configuration allows the amplifier to turn into VHF oscillator, which is highly unwanted in amplifier circuits.
The conclusion of this is that nature and physics always find a way to fuck with you 😂
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