John Larkin's LC oscillator
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From: JosephKK on 15 Jun 2010 01:32 On Mon, 14 Jun 2010 16:56:07 +1000, Grant <omg(a)grrr.id.au> wrote: >On Sun, 13 Jun 2010 12:34:08 -0700, "JosephKK"<quiettechblue(a)yahoo.com> wrote: > >>On 13 Jun 2010 10:19:10 GMT, Jasen Betts <jasen(a)xnet.co.nz> wrote: >> >>>On 2010-06-13, JosephKK <quiettechblue(a)yahoo.com> wrote: >>> >>>> The sim runs but i cannot find the wave file. Where do you think it gets >>>> put when in wine? >>> >>>On mine I found it in the same directory as the asc file. >>> >>> >>>--- news://freenews.netfront.net/ - complaints: news(a)netfront.net --- >> >>Yep. Right where it should be. Don't know why i couldn't find it the >>first time. Thanx. Oops, now i see. Should be a while before i make >>that mistake again. > >Perhaps you forgot to hit the file browser's refresh? > >Grant. Simpler, i failed to read the spice directive correctly.
From: Jim Thompson on 15 Jun 2010 10:21 On Mon, 14 Jun 2010 22:18:22 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Mon, 14 Jun 2010 22:06:53 -0700, >"JosephKK"<quiettechblue(a)yahoo.com> wrote: > >>On Mon, 14 Jun 2010 11:15:00 -0700, Jim Thompson >><To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote: >> >>>On Mon, 14 Jun 2010 10:50:58 -0700 (PDT), dagmargoodboat(a)yahoo.com >>>wrote: >>> >>>>On Jun 14, 12:08�pm, Jim Thompson <To-Email-Use-The-Envelope-I...(a)On- >>>>My-Web-Site.com> wrote: >>>>> On Mon, 14 Jun 2010 09:49:09 -0700 (PDT), dagmargoodb...(a)yahoo.com >>>>> wrote: >>>[snip] >>>>> >>>>> > � � � � Vcc = +5v >>>>> > � �--+--------------+------+-- >>>>> > � � �| � � � � � � �| � � �| >>>>> > � � �| � � � � � � �| � � .-. >>>>> > � � �| � � � � � � �| � � | | e.s.r. = 1 ohm >>>>> > � � �| � � � � � � �| � � | | >>>>> > � � �| � � � � � � �| � � '-' >>>>> > � � �| � � � � � � �| � � �| >>>>> > � � �| � � � � � � �| � � �|_ || >>>>> > � � �| � � � � � � �| � � � _)|| >>>>> > � � .-. � � � � � �--- �L1a _)|| >>>>> > Rb �| | � � � � C1 --- �1mH _)|| >>>>> > 47k | | � � � � 1uF | � � � _)|| >>>>> > � � '-' � � � � � � | � � � _)|| >>>>> > � � �| � � � � � � �| � � *| �|| >>>>> > � � �| � � � � � � �'---+--' �|| >>>>> > � � �| � �R1 � � D1 � � | � � || >>>>> > � � �| � 220r �schottky | � � || >>>>> > � � �+--/\/\/----|>]----+ � � || >>>>> > � � �| � � � � � � � � �| � � || >>>>> > � � �| � � .------------' � � || >>>>> > � � �| � |/ � � � � � � � � � || >>>>> > � � �+---| � �Q1 � � � � � � �|| >>>>> > � � �| � |>. 2n3904 � � � � � || >>>>> > � � �| � � | � � � � � � � * �|| >>>>> > �C2 --- � �+----------------. || >>>>> > 1uF --- � �| � � � � � L1b �_)|| >>>>> > � � �| � � | � � � � 100nH �_)|| >>>>> > � � �| � � | � � � � � � � | >>>>> > � � === � �| � � � � � � �=== >>>>> > � � � � � �| >>>>> > � � � � � �'--------------------> 5KHz output >>>>> >>>>> >Cheers, >>>>> >James Arthur >>>>> >>>>> [snip LTspice Schematic] >>>>> >>>>> James, �How can you call it "class-A" when the emitter current is >>>>> _not_linear_, _not_linear_, _not_linear_, _not_linear_ !! >>>> >>>>True, the emitter current isn't linear, but it is continuous and non- >>>>zero, so I call that "class-A." >>>> >>>> >>>>> All you've done is use a Schottky bypassing the C-B junction... >>>>> otherwise it's identical. >>>> >>>>That makes a big difference. It prevents Q1 saturating and from >>>>conducting b-c. And, without it Q1 conducts in reverse mode during >>>>negative peaks, making the i(c) not just discontinuous, but reversing >>>>in direction. That loads the tank, obviously. >>> >>>"Obviously"? Q1 doesn't conduct in reverse with your values, but no >>>Schottky... the current is always out of the emitter... though it does >>>get awfully close to zero: -376uA and -12.5mA peak. >>> >>>> >>>>> I liken such oscillators to how you push your kid on a swing set. >>>>> Giving a "nudge" every cycle. >>>> >>>>That's exactly how I think of them too. A "nudge" each cycle (short >>>>conduction cycle) is what I did first. I call that "class-C." >>>> >>>>> To be "class-A" you'd need to sit upon the top bars and _continuously_ >>>>> push and pull the ropes. >>>> >>>>Or you can pull continuously, harder at some times, not as hard at >>>>others. That gives the swing position a d.c. bias, but is otherwise >>>>the same, yes? >>> >>>Class-A implies _linear_, does it not? Or do we have a Larkin >>>definition for today ?:-) >>> >> >>The definition i have always heard is that it is conducting through the >>whole cycle. Nothing about linearity. And that is one fougly non-linear >>circuit. > >Only if you want it to be. It can be designed to be a nice smooth >class A oscillator with precise automatic gain control that servoes >oscillation amplitude to almost exactly 2*Vcc, with a low TC. Not bad >for one transistor. > >John So show us. I maintain there is no variable _linear_gain_ element there. As Win says, "Discuss it" :-) ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | The only thing bipartisan in this country is hypocrisy
From: JosephKK on 15 Jun 2010 23:36 On Mon, 14 Jun 2010 22:18:22 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Mon, 14 Jun 2010 22:06:53 -0700, >"JosephKK"<quiettechblue(a)yahoo.com> wrote: > >>On Mon, 14 Jun 2010 11:15:00 -0700, Jim Thompson >><To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote: >> >>>On Mon, 14 Jun 2010 10:50:58 -0700 (PDT), dagmargoodboat(a)yahoo.com >>>wrote: >>> <snip> >>>Class-A implies _linear_, does it not? Or do we have a Larkin >>>definition for today ?:-) >>> >> >>The definition i have always heard is that it is conducting through the >>whole cycle. Nothing about linearity. And that is one fougly non-linear >>circuit. > >Only if you want it to be. It can be designed to be a nice smooth >class A oscillator with precise automatic gain control that servoes >oscillation amplitude to almost exactly 2*Vcc, with a low TC. Not bad >for one transistor. > >John So post that version instead.
From: John Larkin on 15 Jun 2010 23:45 On Tue, 15 Jun 2010 20:36:11 -0700, "JosephKK"<quiettechblue(a)yahoo.com> wrote: >On Mon, 14 Jun 2010 22:18:22 -0700, John Larkin ><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: > >>On Mon, 14 Jun 2010 22:06:53 -0700, >>"JosephKK"<quiettechblue(a)yahoo.com> wrote: >> >>>On Mon, 14 Jun 2010 11:15:00 -0700, Jim Thompson >>><To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote: >>> >>>>On Mon, 14 Jun 2010 10:50:58 -0700 (PDT), dagmargoodboat(a)yahoo.com >>>>wrote: >>>> ><snip> >>>>Class-A implies _linear_, does it not? Or do we have a Larkin >>>>definition for today ?:-) >>>> >>> >>>The definition i have always heard is that it is conducting through the >>>whole cycle. Nothing about linearity. And that is one fougly non-linear >>>circuit. >> >>Only if you want it to be. It can be designed to be a nice smooth >>class A oscillator with precise automatic gain control that servoes >>oscillation amplitude to almost exactly 2*Vcc, with a low TC. Not bad >>for one transistor. >> >>John > >So post that version instead. I did, several days ago. ftp://jjlarkin.lmi.net/LC_YDx.gif And I described it long before that. ftp://jjlarkin.lmi.net/Ships_Bell.JPG I can't help it if people keep over-driving it, and then complaining that it's over-driven. John
From: Jim Thompson on 15 Jun 2010 23:52
On Tue, 15 Jun 2010 20:45:37 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Tue, 15 Jun 2010 20:36:11 -0700, >"JosephKK"<quiettechblue(a)yahoo.com> wrote: > >>On Mon, 14 Jun 2010 22:18:22 -0700, John Larkin >><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >> >>>On Mon, 14 Jun 2010 22:06:53 -0700, >>>"JosephKK"<quiettechblue(a)yahoo.com> wrote: >>> >>>>On Mon, 14 Jun 2010 11:15:00 -0700, Jim Thompson >>>><To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote: >>>> >>>>>On Mon, 14 Jun 2010 10:50:58 -0700 (PDT), dagmargoodboat(a)yahoo.com >>>>>wrote: >>>>> >><snip> >>>>>Class-A implies _linear_, does it not? Or do we have a Larkin >>>>>definition for today ?:-) >>>>> >>>> >>>>The definition i have always heard is that it is conducting through the >>>>whole cycle. Nothing about linearity. And that is one fougly non-linear >>>>circuit. >>> >>>Only if you want it to be. It can be designed to be a nice smooth >>>class A oscillator with precise automatic gain control that servoes >>>oscillation amplitude to almost exactly 2*Vcc, with a low TC. Not bad >>>for one transistor. >>> >>>John >> >>So post that version instead. > >I did, several days ago. > >ftp://jjlarkin.lmi.net/LC_YDx.gif > >And I described it long before that. > >ftp://jjlarkin.lmi.net/Ships_Bell.JPG > >I can't help it if people keep over-driving it, and then complaining >that it's over-driven. > >John Hear yee, hear yee... one time only announcement... it's not a linear AGC'd oscillator... believe Larkin at your own peril :-) ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | The only thing bipartisan in this country is hypocrisy |