Talk:Circuit Idea/How to Help an LC Tank

Starting and maintaining oscillation
(I have copied below the section of the same name from the discussion about LC tank) Circuit-fantasist (talk) 16:43, 20 January 2008 (UTC)

In every kind of oscillator (including LC and relaxation oscillators), there must be at least 2 different components that "remember" 2 "instantaneous values": at any point in the oscillaton, there has to be at least the output voltage value, and also something else that remembers if we are going "up" or "down".
 * It sounds very philosophical. I need time to assimilate this wisdom:) Circuit-fantasist (talk) 08:57, 19 January 2008 (UTC)

Since resistors can instantaneously change current (when voltage is instantaneously changed), they are useless for "remembering".
 * I like this thought; I have inserted it into the story. Circuit-fantasist (talk) 08:57, 19 January 2008 (UTC)

Components that can be used for remembering:
 * capacitors
 * inductors
 * positive-feedback amplifiers (flip-flops, Schmitt trigger inverters, etc.)

In a real LC oscillator, there also is something else that regulates how energy from the power supply is fed into the rest of the circuit -- it "pushes" the rest of the circuit.

Some people use a complicated circuit (op amps, PTR resistors, etc.) that very gently puts in just enough energy to compensate for the parasitic resistance of the LC, making as "pure" a sine wave as possible. There are a variety of less complicated circuits that are perhaps easier to understand, but generate a waveform that is more distorted from the "ideal" sine wave.

Would it help or make things more confusing to discuss an example "pusher" circuit?

--DavidCary (talk) 22:51, 18 January 2008 (UTC)