EMRFD Message Archive 15289

Message	Date	From	Subject
15289	2019-05-26 15:54:52	Alberto I2PHD	Please help me to save some of my hairs...
Is there any kind soul willing to help me saving the last precious hairs remaining on my head ? I am continuously pulling them, trying to make the circuit below working as I intended... It is a crystal Colpitts oscillator. If X1 is 1 MHz or above, no problems, it oscillates. Below that (I tried 100 kHz, 200 kHz, 233 kHz and a few others) ... nothing.... no signs of oscillations. I tried many and many and many capacitor values for C1 and C2, ranging from 100 pF to a few thousands pF, in various combinations. Evidently I missed the right one... A sound Thanks to anybody who will help me... The BC549 is an European NPN transistor, with a hfe of about 500, and a transition frequency of 300 MHz. Alberto
15290	2019-05-26 16:02:46	chuck adams	Re: Please help me to save some of my hairs...
I would try a jumper across CV and see what happens. At 100kHz, 40pF has an X_C of about 40K, if my calculator is working correctly. chuck, k7qo
15291	2019-05-26 16:09:55	Alberto I2PHD	Re: Please help me to save some of my hairs...
On 2019-05-27 1:02, chuck adams chuck.adams.k7qo@gmail.com [emrfd] wrote: I would try a jumper across CV and see what happens. At 100kHz, 40pF has an X_C of about 40K, if my calculator is working correctly. Thanks, but I forgot to say that I had already tried that way, and... no joy.... :-( Alberto
15292	2019-05-26 16:38:42	Harold Smith	Re: Please help me to save some of my hairs...
In my experience, which does not really include such low frequencies, the values of C1 and C2 are either equal or C2 is the larger, sometimes by 5 or 6 times.  Your schematic shows C1 much larger than C2.  Have you tried swapping them? de KE6TI, harold
15293	2019-05-26 17:24:34	Dave Shaw	Re: Please help me to save some of my hairs...
Hi Alberto,                   Have you tried reducing R1 to give it a bit more of a kick. Cheers Dave VK3DHF   Sent from Mail for Windows 10
15294	2019-05-27 01:06:56	Roelof Bakker	Re: Please help me to save some of my hairs...
Hello Alberto, If I remember correct, I have been struggling with this circuit as well. If I remember correct once more, I solved the problem by using a 'normal' DC bias circuit, consisting of a resitor from V+ to the base and another from base to ground. Using high value resistors the loading of the crystal will be minimal. Just try another 390K to ground. 73, Roelof, pa0rdt
15295	2019-05-27 01:37:45	Lasse Moell	Re: Please help me to save some of my hairs...
I just had a quick look/read in my files... Hamradio march 1976 had an interesting article by VK2ZTB regarding crystal oscillators "Survey of Crystal Oscillators". He lists the circuit you have as for 1MHz and up. As crystals for lower frequencies usually have higher ESR and different cut,  the recommended cirucit is pretty much what Roelof said: bias the base with two resistors. Include a resistor at the collector to power, and sample the output at collector. The values give: Rb 100k and 47k (to gnd). Rc 2,2k Re 2,2k. Feedback caps used are 680pF and 1000 pF. IQD, an manufacturer of crystals also do reccomend this circuit for low frequency crystals, and your circuit for >1MHz but with the addition of biasing the base with two resistors. If you NEED this circuit to work, I guess you need to increase the gain, and make sure you have proper feedback. 27 maj 2019 10:06:52 +02:00, skrev 'Roelof Bakker' roelof@ndb.demon.nl [emrfd] :   Hello Alberto, If I remember correct, I have been struggling with this circuit as well. If I remember correct once more, I solved the problem by using a 'normal' DC bias circuit, consisting of a resitor from V+ to the base and another from base to ground. Using high value resistors the loading of the crystal will be minimal. Just try another 390K to ground. 73, Roelof, pa0rdt
15296	2019-05-27 04:12:03	Steve Dick	Re: Please help me to save some of my hairs...
Alberto, save your hair!  You can try lowering R2 to 470 ohms.  The ratio of capacitive reactances for C1 and C2 also play an important role.  Here’s a reference which may help you, though the oscillators discussed don’t go below 1 MHz.  According to the referenced article, try capacitive reactance of C1 = 25 ohms and capacitive reactance of C2 = 40 ohms at frequency of interest. -Steve K1RF http://yu1lm.qrpradio.com/HF-VHF%20universal%20oscillator-YU1LM.pdf
15297	2019-05-27 09:26:16	Raj	Re: Please help me to save some of my hairs...
Try proportionately larger values for C1 C2 and Cv or even short Cv. Like for 100khz should have C1 C2 in nF and not pf. It WILL oscillate. Raj At 27-05-19, you wrote: > > >Is there any kind soul willing to help me saving the last precious hairs remaining on my head ? > >I am continuously pulling them, trying to make the circuit below working as I intended... > > >It is a crystal Colpitts oscillator. If X1 is 1 MHz or above, no problems, it oscillates. > >Below that (I tried 100 kHz, 200 kHz, 233 kHz and a few others) ... nothing.... no signs of oscillations. > >I tried many and many and many capacitor values for C1 and C2, ranging from 100 pF to a few thousands pF, in various combinations. >Evidently I missed the right one... > > >A sound Thanks to anybody who will help me...
15298	2019-05-27 09:27:37	Norberto Modanesi	Re: Please help me to save some of my hairs...
Alberto: This is the oscilator used by Atlas 210 as marker oscillator (100KHz) 73 Norberto – LU5DNM El lun., 27 may. 2019 a las 8:12, 'Steve Dick' sbdick@optonline.net [emrfd] (<emrfd@yahoogroups.com>) escribió: > > > Alberto, save your hair! You can try lowering R2 to 470 ohms. The ratio > of capacitive reactances for C1 and C2 also play an important role. Here’s > a reference which may help you, though the oscillators discussed don’t go > below 1 MHz. According to the referenced article, try capacitive reactance > of C1 = 25 ohms and capacitive reactance of C2 = 40 ohms at frequency of > interest. > -Steve K1RF > > http://yu1lm.qrpradio.com/HF-VHF%20universal%20oscillator-YU1LM.pdf > > *
15299	2019-05-27 13:21:20	Alberto I2PHD	Re: Please help me to save some of my hairs...
On 2019-05-27 13:12, 'Steve Dick' sbdick@optonline.net [emrfd] wrote: Alberto, save your hair!  You can try lowering R2 to 470 ohms.  The ratio of capacitive reactances for C1 and C2 also play an important role.  Here’s a reference which may help you, though the oscillators discussed don’t go below 1 MHz.  According to the referenced article, try capacitive reactance of C1 = 25 ohms and capacitive reactance of C2 = 40 ohms at frequency of interest. -Steve K1RF http://yu1lm.qrpradio.com/HF-VHF%20universal%20oscillator-YU1LM.pdf Dear friends,   thanks for all the suggestions received so far, very appreciated. I tried a few of them, with no success. I will read now the document from Steve, changing accordingly my circuit. But, as I wrote, my oscillator *does* oscillate from 1 MHz up.... Another possibility is to change the active element, maybe using a JFET... I have some J310 in my junk box, perhaps the higher input impedance of a JFET compared to a bipolar can make the difference. As a matter of facts, most of the example circuits found on the various books do use a FET as oscillator... My hairs are in a temporary hold status...  :-) -- 73 Alberto I2PHD <<< http://www.weaksignals.com >>>
15300	2019-05-27 13:23:27	Alberto I2PHD	Re: Please help me to save some of my hairs...
On 2019-05-27 15:26, Norberto Modanesi norberto.modanesi@gmail.com [emrfd] wrote: This is the oscilator used by Atlas 210 as marker oscillator (100KHz) 73 Norberto – LU5DNM Norberto,   did you perhaps forget to attach a file to your message ? -- 73 Alberto I2PHD <<< http://www.weaksignals.com >>>
15301	2019-05-27 14:45:12	Lasse Moell	Re: Please help me to save some of my hairs...
Alberto, you cannot give up that easy! Have a talk to Mr Barkhausen about his criteria :) Try to measure the low frequency crystals to see their parameters, and run some simulatioons to verify that you do meed gain and phase critera for oscillation. I guess that your MHz-crystals are AT cut and the lower frequency crystals have a different cut, and higher esr. As for a final suggestion, try build a stable amplifier I am convinced it will oscilalte :) /Lasse SM5GLC 27 maj 2019 22:21:17 +02:00, skrev Alberto I2PHD i2phd@weaksignals.com [emrfd] :   On 2019-05-27 13:12, 'Steve Dick' sbdick@optonline.net [emrfd] wrote: Alberto, save your hair!  You can try lowering R2 to 470 ohms.  The ratio of capacitive reactances for C1 and C2 also play an important role.  Here’s a reference which may help you, though the oscillators discussed don’t go below 1 MHz.  According to the referenced article, try capacitive reactance of C1 = 25 ohms and capacitive reactance of C2 = 40 ohms at frequency of interest. -Steve K1RF http://yu1lm.qrpradio.com/HF-VHF%20universal%20oscillator-YU1LM.pdf Dear friends,   thanks for all the suggestions received so far, very appreciated. I tried a few of them, with no success. I will read now the document from Steve, changing accordingly my circuit. But, as I wrote, my oscillator *does* oscillate from 1 MHz up.... Another possibility is to change the active element, maybe using a JFET... I have some J310 in my junk box, perhaps the higher input impedance of a JFET compared to a bipolar can make the difference. As a matter of facts, most of the example circuits found on the various books do use a FET as oscillator... My hairs are in a temporary hold status...  :-) -- 73 Alberto I2PHD <<< http://www.weaksignals.com >>>
15302	2019-05-27 15:35:58	Alberto I2PHD	Re: Please help me to save some of my hairs...
On 2019-05-27 23:45, 'Lasse Moell' lasse.moell@webdog.se [emrfd] wrote: As for a final suggestion, try build a stable amplifier I am convinced it will oscilalte :) Lasse,    that is indeed a very clever suggestion... :-)  Verified in practice many times.... If everything else fails, I'll do that ! -- 73 Alberto I2PHD <<< http://www.weaksignals.com >>>
15303	2019-05-27 15:43:45	Norberto Modanesi	Re: Please help me to save some of my hairs...
Alberto: I'm sure I didn't forget to attach the file.- Here's again anyway.- 73 Norberto - LU5DNM El lun., 27 may. 2019 a las 18:45, 'Lasse Moell' lasse.moell@webdog.se [emrfd] (<emrfd@yahoogroups.com>) escribió: > > > Alberto, > you cannot give up that easy! Have a talk to Mr Barkhausen about his > criteria :) > > Try to measure the low frequency crystals to see their parameters, and run > some simulatioons to verify that you do meed gain and phase critera for > oscillation. > > I guess that your MHz-crystals are AT cut and the lower frequency crystals > have a different cut, and higher esr. > > As for a final suggestion, try build a stable amplifier I am convinced it > will oscilalte :) > /Lasse SM5GLC > > 27 maj 2019 22:21:17 +02:00, skrev Alberto I2PHD i2phd@weaksignals.com > [emrfd] <emrfd@yahoogroups.com>: > > > > > On 2019-05-27 13:12, 'Steve Dick' sbdick@optonline.net [emrfd] wrote: > > > Alberto, save your hair! You can try lowering R2 to 470 ohms. The ratio > of capacitive reactances for C1 and C2 also play an important role. Here’s > a reference which may help you, though the oscillators discussed don’t go > below 1 MHz. According to the referenced article, try capacitive reactance > of C1 = 25 ohms and capacitive reactance of C2 = 40 ohms at frequency of > interest. > -Steve K1RF > > http://yu1lm.qrpradio.com/HF-VHF%20universal%20oscillator-YU1LM.pdf > > > Dear friends, > > thanks for all the suggestions received so far, very appreciated. I > tried a few of them, with no success. > I will read now the document from Steve, changing accordingly my circuit. > But, as I wrote, my oscillator *does* oscillate from 1 MHz up.... > Another possibility is to change the active element, maybe using a JFET... > I have some J310 in my junk box, perhaps the higher input impedance of a > JFET compared to a bipolar can make the difference. As a matter of facts, > most of the example circuits found on the various books do use a FET as > oscillator... > > My hairs are in a temporary hold status... :-) > > -- > > *73 Alberto I2PHD <<< http://www.weaksignals.com > > <http://www.weaksignals.com>>>* > > > > > -- Norberto Modanesi norberto.modanesi@gmail San Nicolas [Non-text portions of this message have been removed]
15304	2019-05-28 01:55:13	Alberto I2PHD	Re: Please help me to save some of my hairs...
On 2019-05-28 0:11, Norberto Modanesi norberto.modanesi@gmail.com [emrfd] wrote: Alberto: I'm sure I didn't forget to attach the file.- Here's again anyway.- 73 Norberto - LU5DNM Norberto, thanks for your help, but then something must be broken... I receive the group messages with Thunderbird, but your message does not have any attachment... is anybody else in the group able to see the attachment ? I also tried to read your message using the Web interface, but also in this case I am unable to find an attachment, or a link to a file... Sorry for the disturbance this may cause to you. BTW, at the end of your message there is this note from Yahoo : [Non-text portions of this message have been removed] Don't know if this could be the reason for the problem... -- 73 Alberto I2PHD <<< http://www.weaksignals.com >>>
15305	2019-05-28 02:32:01	michael rogers	Re: Please help me to save some of my hairs...
Alberto,Perhaps the linked article waswhat  referred to.But attached  here is the schematic of the ATLAS 210X 100kHz xtal oscillator. Michael 2E0IHW
15306	2019-05-28 02:32:58	Lasse Moell	Re: Please help me to save some of my hairs...
Lets see if I manage to attach a pic of the Atlas 100kHz oscillator :) /Lasse 28 maj 2019 10:55:09 +02:00, skrev Alberto I2PHD i2phd@weaksignals.com [emrfd] <emrfd@yahoogroups.com>: > > > > > > On 2019-05-28 0:11, Norberto Modanesi <norberto.modanesi@gmail.com> [emrfd] wrote: > > > > Alberto: > > I'm sure I didn't forget to attach the file.- > > Here's again anyway.- > > 73 > > Norberto - LU5DNM > > > > Norberto, thanks for your help, but then something must be broken... I receive the group messages with Thunderbird, but your message does not have any attachment... is anybody else in the group able to see the attachment ? > > I also tried to read your message using the Web interface, but also in this case I am unable to find an attachment, or a link to a file... > Sorry for the disturbance this may cause to you. > > BTW, at the end of your message there is this note from Yahoo : [Non-text portions of this message have been removed] > > Don't know if this could be the reason for the problem... > > -- > > 73 Alberto I2PHD > <<< http://www.weaksignals.com > <http://www.weaksignals.com>>> > > [Non-text portions of this message have been removed]
15307	2019-05-28 02:40:17	Lasse Moell	Re: Please help me to save some of my hairs...
Nope, didi not work at all :) But I sent the scheamtic to you Alberto. And this webpage do offer some suggestions
15308	2019-05-28 03:06:37	Alberto I2PHD	Re: Please help me to save some of my hairs...
On 2019-05-28 11:40, 'Lasse Moell' lasse.moell@webdog.se [emrfd] wrote: Nope, didi not work at all :) But I sent the scheamtic to you Alberto. And this webpage do offer some suggestions on very simple 100 kHz oscillator. It may be what you want/need, https://www.radioexperimenter.us/rm-1967-03/ant-1.html Lasse and Michael,    thanks for sending the schematic of the Atlas 100 kHz calibrator. It showed up in my inbox only for the copy of your message sent directly to my email address. So it is confirmed that this Yahoo group does not allow attachments to messages.... If I were the administrator, I would switch to groups.io, as I have already done for the 5 groups I administer...  The switch was painless, and I would not go back. Very interesting the schematic contained in the document referred by you Lasse... this evening I will try it. My ultimate goal is to build a very simple poor-man-calibrator/crystal-tester, with two fixed frequencies, 100 kHz and 1 MHz, and a socket on the panel where to insert an external xtal... with the three options switchable. If everything else fails, I will drop the option for the 100 kHz.... or use an IC oscillator, with a couple of inverting buffers, polarized in the analog region... that configuration makes *any* xtal to oscillate.... :-) -- 73 Alberto I2PHD <<< http://www.weaksignals.com >>>
15310	2019-05-28 08:27:50	Ken Chase	Re: Please help me to save some of my hairs...
Why not start with a 1 MHZ crystal and divide by 10, then filter if necessary. 73 Ken VA3ABN
15311	2019-05-28 08:28:00	Norberto Modanesi	Re: Please help me to save some of my hairs...
I'm sorry Alberto. I may have a trouble with my e-mail account.- I've uploaded the schematic to the files area of the group (Atlas.jpg).- 73 El mar., 28 may. 2019 a las 7:10, Alberto I2PHD i2phd@weaksignals.com [emrfd] (<emrfd@yahoogroups.com>) escribió:   On 2019-05-28 11:40, 'Lasse Moell' lasse.moell@webdog.se [emrfd] wrote: Nope, didi not work at all :) But I sent the scheamtic to you Alberto. And this webpage do offer some suggestions on very simple 100 kHz oscillator. It may be what you want/need, https://www.radioexperimenter.us/rm-1967-03/ant-1.html Lasse and Michael,    thanks for sending the schematic of the Atlas 100 kHz calibrator. It showed up in my inbox only for the copy of your message sent directly to my email address. So it is confirmed that this Yahoo group does not allow attachments to messages.... If I were the administrator, I would switch to groups.io, as I have already done for the 5 groups I administer...  The switch was painless, and I would not go back. Very interesting the schematic contained in the document referred by you Lasse... this evening I will try it. My ultimate goal is to build a very simple poor-man-calibrator/crystal-tester, with two fixed frequencies, 100 kHz and 1 MHz, and a socket on the panel where to insert an external xtal... with the three options switchable. If everything else fails, I will drop the option for the 100 kHz.... or use an IC oscillator, with a couple of inverting buffers, polarized in the analog region... that configuration makes *any* xtal to oscillate.... :-) -- 73 Alberto I2PHD <<< http://www.weaksignals.com >>>
15312	2019-05-28 09:50:39	Alberto I2PHD	Re: Please help me to save some of my hairs...
On 2019-05-28 12:14, Ken Chase chase8043@gmail.com [emrfd] wrote: Why not start with a 1 MHZ crystal and divide by 10, then filter if necessary. Perfectly doable, but it would contravene the principle which I mostly adhere to, the KISS principle.... :-) -- 73 Alberto I2PHD <<< http://www.weaksignals.com >>>
15313	2019-05-28 09:53:13	Alberto I2PHD	Re: Please help me to save some of my hairs...
On 2019-05-28 15:14, Norberto Modanesi norberto.modanesi@gmail.com [emrfd] wrote: I'm sorry Alberto. I may have a trouble with my e-mail account.- I've uploaded the schematic to the files area of the group (Atlas.jpg).- 73 No reason to be sorry Norberto, it's not your fault.... Yahoo does not allow on this group attachments to messages, that's why your two attempts did fail.... Thanks for uploading the schematic to the file area of the group. -- 73 Alberto I2PHD <<< http://www.weaksignals.com >>>
15314	2019-05-28 10:03:16	John Marshall	Re: Please help me to save some of my hairs...
Norberto and all, There is nothing wrong with your email account. This group does not permit email attachments. Uploading to files or photos works fine. See the group settings: < https://groups.yahoo.com/neo/groups/emrfd/info >. 73, John, KU4AF Pittsboro, NC >
15315	2019-05-28 10:19:27	Ken Chase	Re: Please help me to save some of my hairs...
I'm only suggesting this method if you are in a hurry for the oscillator. If you are, then you can go back to working with a 100 khz crystal. 73 Ken VA3ABN
15316	2019-05-28 11:59:38	sgatzeh	Re: Please help me to save some of my hairs...
Hi, I just found an application for a 100 kHz xal osc, please see http://www.rainers-elektronikpage.de/VALVO-Schaltungssammlungen/02_09.pdf 73 Henning Weddig DK5LV -----Ursprüngliche Mitteilung----- Von: Ken Chase chase8043@gmail.com [emrfd] An: EMRFD Verschickt: Di, 28. Mai 2019 19:19 Betreff: Re: [emrfd] Please help me to save some of my hairs...   I'm only suggesting this method if you are in a hurry for the oscillator. If you are, then you can go back to working with a 100 khz crystal. 73 Ken VA3ABN
15317	2019-05-28 12:10:42	Lasse Moell	Re: Please help me to save some of my hairs...
I guess Alberto is swamped with oscillator circuits for low frequency crystals by now. But that does not answer the question why his oscillator did not function at low frequencies? What changes have to be done to get it to oscillate on frequencies below 1 MHz?? Maybe someone who enjoy spice  can analyze the original circuit and see if the gain and phasechange are meeting the oscilator critera? /Lasse SM5GLC 28 maj 2019 20:59:33 +02:00, skrev sgatzeh HWeddig@aol.com [emrfd] :   Hi, I just found an application for a 100 kHz xal osc, please see http://www.rainers-elektronikpage.de/VALVO-Schaltungssammlungen/02_09.pdf 73 Henning Weddig DK5LV -----Ursprüngliche Mitteilung----- Von: Ken Chase chase8043@gmail.com [emrfd] An: EMRFD Verschickt: Di, 28. Mai 2019 19:19 Betreff: Re: [emrfd] Please help me to save some of my hairs...   I'm only suggesting this method if you are in a hurry for the oscillator. If you are, then you can go back to working with a 100 khz crystal. 73 Ken VA3ABN
15318	2019-05-29 06:40:22	Alberto I2PHD	Re: Please help me to save some of my hairs...
On 2019-05-28 21:10, 'Lasse Moell' lasse.moell@webdog.se [emrfd] wrote: Maybe someone who enjoy spice  can analyze the original circuit and see if the gain and phasechange are meeting the oscilator critera? Success, at last! Steve Ratzlaff AA7U was so kind, in pure ham spirit, to design, solder and test a small 100 kHz oscillator, and he sent the schematic to me : Not much different from those I had already tested, but that capacitors combination is different from those I tried. I used a 2N3904 instead of the 2N2222, as I had the former handy. And it worked : Many thanks indeed Steve ! About simulating the circuit, I have LTSpiceIV, but it does not have the model of a crystal... otherwise I would have simulated many configurations before melting solder... Thanks to all who gave advice and suggestions.  -- 73 Alberto I2PHD <<< http://www.weaksignals.com >>>
15319	2019-05-29 08:24:30	Dana Myers	Re: Please help me to save some of my hairs...
15320	2019-05-30 06:45:02	biastee	Re: Please help me to save some of my hairs...
I analyzed I2PHD's oscillator using Harada's forward transmission method. The 100 kHz crystal was modeled with the parameters on Kraus' website. However, I substituted Q1 with BC547B because it was what I had at hand. The conditions for oscillation are: 1. transmission phase = 0 degree and 2. gain at 0 phase > 1. At zero phase, I2PHD's gain is less than 1. So, it doesn't fulfill the conditions for oscillation. However, inserting a 4 mH inductor (Le) in series with R2 enables the conditions to be fulfilled. This is how Le enables oscillation: R2 loads the resonator. Le reduces the loading by R2, hence increasing the gain margin. Equivalent circuit model and design file are available at the link below: https://sites.google.com/site/randomwok/Home/electronic-projects/crystal-oscillator-1-mhz
15321	2019-05-30 10:07:22	Alberto I2PHD	Re: Please help me to save some of my hairs...
On 2019-05-30 15:41, biastee@yahoo.com [emrfd] wrote: Equivalent circuit model and design file are available at the link below: https://sites.google.com/site/randomwok/Home/electronic-projects/crystal-oscillator-1-mhz Thanks OM (don't have your name),    I have problems in recognizing your schematic : as equivalent to what I used, but the culprit is on me, as I am rather deficient in RF design, as many of you have already understood, seen my problems in making a simple circuit to oscillate... I am quite sure you are right, will try to put an inductor in series with the emitter resistor of my original circuit, just to see the effects. Many thanks also for the motional data of the crystal, which I will try to use in LTSpice. Same thanks also to Dana Myers who reported the same data as published by Orcad. -- 73 Alberto I2PHD <<< http://www.weaksignals.com >>>
15323	2019-05-30 22:17:10	biastee	Re: Please help me to save some of my hairs...
My previous comment didn't touch
15324	2019-06-02 04:00:20	jim_amos_n8cah	Re: Please help me to save some of my hairs...
I built a 50KHz oscillator for a PCMCIA Wi-Fi radio project I as part of.   The basic requirements were 3.3V, low power,  and small.  It also needed to start reliably the industrial temperature range (-40 to +85C).  After experimenting with a bunch of typologies, I concluded that a circuit using a 74HC04 using the Pierce-Gate topology worked best after prototyping and measuring several circuits.   I don't remember if I tried any discrete transistor designs though.    Information on this circuit is pretty widely available on the internet. Alberto, great job on simulating and root causing why the BJT circuit wasn't working! 73's Jim N8CAH
15325	2019-06-02 07:48:29	Alberto I2PHD	Re: Please help me to save some of my hairs...
On 2019-06-02 13:00, jimamos@sbcglobal.net [emrfd] wrote: After experimenting with a bunch of typologies, I concluded that a circuit using a 74HC04 using the Pierce-Gate topology worked best after prototyping and measuring several circuits.  Yes, a couple of CMOS gates, polarized in their linear region and wired so that the crystal acts as feedback network, make almost any crystal to oscillate... I read somewhere words to the effect that this could cause the crystal to break, given too big an excitation, but, as far as I know, there are no reports of this actually happening. -- 73 Alberto I2PHD <<< http://www.weaksignals.com >>>
15326	2019-06-02 08:36:04	Dana Myers	Re: Please help me to save some of my hairs...
15327	2019-06-02 08:49:49	Dana Myers	Re: Please help me to save some of my hairs...