jason9

modified 7 years ago

What kind of oscillator is this

691

17:06:58

It seems very simple and yet it is a design I have never seen before as an official design.

Edit: I adjusted the way the components are laid out in the schematic and now it looks something like a highly reduced Colpitts oscillator.

Edit2: This turns out to be a Pierce oscillator. I wasn’t very familiar with it so I didn’t recognize it and in the schematics it shows a crystal instead of an inductor and a NOT gate symbol instead of the transistor-resistor NOT gate here.

published 7 years ago

abobaker

7 years ago

Yes this configuration is not very popular, however I've tried it before in real life and it works well, but I think it's not popular because it can not go to high frequencies because of miller and Rc ... Also I like to arrange it this way it's easier to see the feedback loop http://everycircuit.com/circuit/6555311652732928

Issacsutt

7 years ago

That's pretty cool

Issacsutt

7 years ago

Could you come up with something that simple for a square wave oscillator? (Not like the classic astable multivibrator)

jason9

7 years ago

@abobaker, I’ve managed to push it to a little over 1GHz (but not further) in simulation by adjusting the base-ground capacitor to account for the base-emitter parasitic capacitor in the transistor. Even removing the base-ground capacitor entirely and making the collector-ground capacitor the same value as the base-emitter parasitic capacitor while reducing the inductor to 2.2nH pushes it as far as I could get it to go.

jason9

7 years ago

Actually, at 1.3nH it gets to 1.6GHz, although at any lower of an inductor value the oscillations stop rising and start diminishing (even at 1.3nH it barely rises, so I have to briefly set the 10kOhm resistor to 1kOhm and then set it back to 10kOhms to get the oscillations going in a reasonable time period).

jason9

7 years ago

I looked at your link and upon readjusting it a little further I’ve come up with this. Looks like a highly reduced Colpitts oscillator to me.

jason9

7 years ago

@issacsutt, I’m not sure I can do that. I actually made this after reverse-engineering @thebugger’s “Simplest 1.5GHz Oscillator”. I’ve also found out that this seems to be a highly reduced version of a known oscillator, not an entirely new oscillator. So, unless someone can reduce a known square-wave oscillator to very few components, I’m not sure it’s possible to produce square-waves with such few components. I’ll give it a try though. Maybe I can figure something out.

jason9

7 years ago

Well, I managed to do it! It isn’t a simplified version of a known square-wave oscillator, but a variation on this very oscillator. I basically just added a BJT to amplify the sine-wave to strong clipping producing a square-wave.

Issacsutt

7 years ago

Ah, not a pure square wave oscillator, a sine wave generator at its heart... I was afraid of that :(

jason9

7 years ago

Why were you afraid of that?

Issacsutt

7 years ago

Because there's not many variations of square wave oscillator out there, other than just an astable, the rest are usually sine wave, or just a bunch of ICs

Issacsutt

7 years ago

You like to analyze the bugger's circuits quite often huh?

hurz

7 years ago

This configuration is very popular, but use nomaly an inverter gate/amp and called pirce oscillator. Instead of an LC pi filter for 180° phase shift a crystal is used. Whats also not perfect is some dampening R is missing. Anyway its a very popular way to build an oscillator.

jason9

7 years ago

Actually, I don’t analyze his circuits that often. I just felt like figuring out how that particular one worked.

jason9

7 years ago

I’ve looked up Pierce oscillator and made one in EC (inductor instead of crystal) and compared it to this circuit and it is indeed very similar. If the BJT-resistor is seen as an inverter (which it is), then this is exactly a Pierce oscillator.

zorgrian

7 years ago

Nice

hurz

7 years ago

You wasn't very familiar with it? Sounds like buggzy

jason9

7 years ago

It’s not like I specifically studied oscillator designs or went to some school for it. I mostly just look things up on wikipedia when I feel like it and learn about how circuits work on here.

zorgrian

7 years ago

Pierce oscillation is usually used in very simple inverter style crystal oscillators, where the gain of the buffer/ invertor is high. Its interesting that many highly stable Colpitts oscillators are designed around an emitter follower BJT amp that has a voltage gain of below one! The needed voltage gain in such a circuit comes from the LC or crystal filter network.

hurz

7 years ago

Right.

jason9

7 years ago

Actually, to be honest, I was only aware of the common-emitter design and now that I search “Colpitts” on here I see the designs of common-emitter, common-base, and common-collector. I also see that the common-collector has one capacitor smaller than the other so that it creates higher voltages to produce the necessary voltage gain while the common-collector amplifies its current so that the oscillations can increase.

zorgrian

7 years ago

Hmmm

zorgrian

7 years ago

I'm considering starting another account with a nice description of a fictitious person aged 8 - 10

jason9

7 years ago

Come on, you don’t need to make fun of me. Are you really so certain that I can’t be 13? Considering the number of members EC has, there has to be a considerable chance that one extra bright kid or other is gonna be on here, so that mean you don’t have to think, and probably shouldn’t think, that I’m not really 13.

hurz

7 years ago

How long is an average human 13 years old. 3 to 4 years? Hmmmm

jason9

7 years ago

Let’s say there is someone like me, and he might be 10-15 or so. Being 13 should be just as likely as being 10 or being 15. Nothing special about it. It shouldn’t matter that I am exactly 13, but that I am in the 10-15 age range.

zorgrian

7 years ago

Hmmm

zorgrian

7 years ago

Jason13 maybe you are born on a leap year (Feb 29)? So you may really be 52?

jason9

7 years ago

I was born March 2nd 2005. Why can’t you just get it in your head that I’m 13 and happen to be slightly more talented than the average 13 year old? There is a kid that goes to the same middle school as I do and he is 11 (at this time of year most 6th graders are 11 years old and a few are 12 years old) but he is considered a 7th grader by the school and he has an 8th grade schedule and he says he gets A in all his subjects. I’m 13 (8th grade) and I am not a grade higher than my age and I have a schedule that is not a year ahead of my grade and I don’t get A in all my subjects. I just happen to have a talent for and interest in electronics. I do not pretend or think to be the best or smartest or whatever kid around. There definitely are kids way smarter than me and there is even one who I happen to know in my school with a population of no more than 1200 kids.

jason9

7 years ago

If you’re really considering the ultra rare possibility that I was born on February 29th (only one in 1461 people are born on that date) then why can’t you just accept the possibility that I happen to have some talent in electronics? Me having talent in electronics can’t be so much more likely than me being born on February 29th that you will consider that possibility but not the possibility of me being a talented kid. And anyway, I would just have my birthday on February 28th or March 1st on non-leap years so that my age number is not one fourth of what it should be. And if you say I have adult vocabulary that not many 13 year olds have, that is because I happen to enjoy reading, particularly on wikipedia and other adult-level language sites with sciency stuff on them. I just happen to have a love for anything sciency especially electronics but also chemistry and physics and stuff too.

hurz

7 years ago

Im sure you are 37 years old and working for the FBI 😵 who cares. I teach kids in the neighborhood electronic. The age of them is in average maybe <14years the older ones will start an apprentership next year and i will keep an eye on them 😁 they have all different talents, sure. I wish there were more kids which have just 1% of your talent! Anyway, they have fun and do know early what they want as a professional. Many kids do not know what they want or whats best for them. So its not only a matter of how intelligent you are, its more importante to be happy with your life and you know whats coming next.

zorgrian

7 years ago

Jason13, I do not care what age you really are.

zorgrian

7 years ago

You do not communicate with a style concomitant with an advanced 13 year old.

hurz

7 years ago

@zorg, yes you care!

jason9

7 years ago

Then what style do I communicate with? How does that compare to that of an advanced 13 year old?

zorgrian

7 years ago

What is an advanced 13 year old? What measure do you use? How is the state of our civilization? How advanced is a tribe of people who live in equilibrium with their environment? What knowledge does an advanced person or civilization possess? Is it precocious of you to describe yourself as advanced?

zorgrian

7 years ago

@hurz , no i do not care what age jason9 is. I care about the values he (she) it projects

zorgrian

7 years ago

This person seems much like another user we know here @B. ??????

zorgrian

7 years ago

Same argument style, similar logic, but without the AM is FM VHF, modes of modulation are bound to frequency, and other odd ideas. At least Jason does not insist on such weird notions despite being reminded again and again of the inaccurate perception

zorgrian

7 years ago

Having said this.... I admire anyone who desires to learn

zorgrian

7 years ago

@B & @J are both prolific contributors of circuits on EC

jason9

7 years ago

@B is @thebugger?

jason9

7 years ago

As far as I know, I try my best to answer all the questions someone has if possible. @thebugger simply ignores questions that prove him wrong. I believe I would look at that question and either give a suitable counter argument for it or concede to the other person’s idea rather than simply ignoring the question.

eekee

7 years ago

I think... at age 13... I communicated in a significantly 'older' style than jason9.

Antonius

1 year ago

Looks like you're using the transistor as an amplifier with a pi filter as a feedback network. I use a 4-stage pi filter on my power supply circuit on my profile. Your circuit specifically looks like a common-base Colpitts oscillator. There's a related circuit called a Hartley oscillator using a T filter instead (2 inductors, 1 capacitor).

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