Hey everyone!
Long time lurker, first time poster. I'm a fourth year electrical engineering student, my major is geared more towards power applications/renewable energy but have always been interesting in radio engineering (it's what actually got me into electrical engineering) and I'm a bit ashamed to ask such a basic question. I've been trying to build a basic wireless switch for a while now and came across some circuits online. While researching I've encountered the Colpitts oscillator (to generate a carrier frequency) a few times but I can't seem to figure out how it works (I hate building circuits without understanding the ins and outs of it).
I'm trying to figure out this one, in particular: http://www.learnabout-electronics.org/Oscillators/images/Colpitts-01.gif
I understand that we need a positive feedback at the required frequency for oscillation to occur, negative feedback to stabilize the output and some form of amplification. However, I really need someone to explain to significance of each component in the circuit (no need to explain the tank circuit, and the fact that the transistor is in essence an amplifier)
And if it's not too much to ask an explanation for this circuit, as well: http://www.pyroelectro.com/projects/pyro_rf_transmitter_27mhz/img/oscillator_theory.png
Thanks in advance!
Long time lurker, first time poster. I'm a fourth year electrical engineering student, my major is geared more towards power applications/renewable energy but have always been interesting in radio engineering (it's what actually got me into electrical engineering) and I'm a bit ashamed to ask such a basic question. I've been trying to build a basic wireless switch for a while now and came across some circuits online. While researching I've encountered the Colpitts oscillator (to generate a carrier frequency) a few times but I can't seem to figure out how it works (I hate building circuits without understanding the ins and outs of it).
I'm trying to figure out this one, in particular: http://www.learnabout-electronics.org/Oscillators/images/Colpitts-01.gif
I understand that we need a positive feedback at the required frequency for oscillation to occur, negative feedback to stabilize the output and some form of amplification. However, I really need someone to explain to significance of each component in the circuit (no need to explain the tank circuit, and the fact that the transistor is in essence an amplifier)
And if it's not too much to ask an explanation for this circuit, as well: http://www.pyroelectro.com/projects/pyro_rf_transmitter_27mhz/img/oscillator_theory.png
Thanks in advance!