Colpitts Oscillator Circuit Analysis (7 - Oscillators)

Let's design a radio frequency Colpitts Oscillator together. We'll be using a common-emitter configuration bipolar transistor.

Aaron Danner is a professor in the Department of Electrical and Computer Engineering at the National University of Singapore.

Video filmed and edited by Cheryl Lim.
@randomcheryl

[alessandrolurgo]

I am an aerospace engineer and a very beginner Electronics Amateur. You videos are the best I have found so far.
My only wish is that you keep up with the good job!

Thanks

[grebulocities]

I've been tinkering with building simple ham radio circuits, and I kept finding various transmitter designs based on Colpitts oscillators hard to understand. Now I get what's going on - Colpitts oscillators are just an amplifier hooked up to an LC tank circuit in a way that creates positive feedback into the amplifier's input. I built a circuit for the lower HF range (about 3.5-5.5 MHz) following your schematic, using a variable capacitor as one of the capacitors and using it to vary the frequency. Not only does it work the way I expected, but I finally understand why now! Thanks for such a clear explanation!

[rickjljr]

This is by far the best L-C oscillator analysis I've seen on You Tube.
The only thing I would do different is to add a section to emphasize the physics of the resonator tank circuit and the transformer like qualities of C1 - C2 and L in the resonator network i.e. A=-C1/C2 (gain required).

[wagsman]

Brilliantly clear. Thanks again. Hope your channel grows exponentially, you have a gift for explaining things.

[matthiasfreiburghaus]

This video is incredibly good. And the same can be said about the rest of your videos. The way you develop a topic is just perfect. I am very happy I came across your chanel, and I hope many will find it.

[GBP]

brilliant work, thank you for going over the the theory and implementing it with a design and explaining every component of the design

[jeremiahsinwon]

I am glad to have you even though I just started watching your videos.

[shawncalderon]

I am new to electrical engineering and find this presentation helpful. Thank you for making the complex understandable.

[amazagx]

Aaron, your videos are great!!
Your contents deserve many more subscribers!!

Thank you very much!!

[jwd.t]

Excellent presentation. Learning my things again in a new way.

[laurentthommet]

This is extremly Wellington explained. Greetings from France

[liviuflorinelanghel]

Hi Aaron Danner! Thank you for your detailed explanations. Now I can say that I understand how this kind on oscillator works. Please, can you also explain the Pierce oscillator or the crystal oscillator often used in the Z80 processor schematics. I mean the one that use two 74LS04 inverter ICs that have feedback resistors, two capacitors and a crystal quartz. Unfortunately I cannot attach a picture of the schematic and also the online schematics I found do not provide a secured link.

[stefano.a]

Very good explanation. Only one note: the circuit at time 5:49 is not an common emitter because of the presence of RG

[XxGoldenXxful]

What parameters do I have to change to get a 2.4 GHz frequency? What is the value of the capacitor and inductor?

[adrian_spdef]

Does it make sense to add another CB transistor to cancel the Miller effect? Or is it irrelevant in that oscillator?

[sifirzero]

Hello, can you explain the example of a metal detector with search coil head? great explanation

[msazid]

Analysis is included with load impedance.. say 50ohm is the load impedance then how will the analysis affected by load impedance and what will be the reflection from the load

[kel-A-]

Other than the feedback network, is there anything else we need to alter in order to achieve higher frequencies?

[hectorbarrera]

Nice video, hope you could made a practical design for high frequencies.

[runforitman]

How does the LC tank provide the extra 180 degrees of phase shift required? I've tried AC analysis, but I could only find an extra 90 degrees