#123

[@SuburbanDon]

Whenever I'm feeling down I watch a W2AEW video and the world doesn't seem so bad anymore. Thanks for all of these great video's you've made.

[@w2aew]

W2AEW video therapy - love it!

[@kamurashev]

Almost exactly how I did it back in the days. I used a 8-12mm drill bit sharpened as a trident so that the central pin was a very bit longer than the side ones. It allowed the bit to center itself when operating. I used a simple hand operated drill to cut stuff. Later I switched to a piece of hacksaw blade sharply broken so that I could cut the rectangulars. I was 14-16 when I did the most of my experiments. Before the things went so messed up. And now I don't even have time for it which makes me feel really bad. I'm just working and working for my family to have a roof above their heads. After we had to storm out when that hell in Ukraine started. Thanks for the videos again - it's like a fresh air breath.

[@dancross2089]

FYI, something I've found helps with the "grabbing" problem: take a slightly damp paper towel, put it on the drill press's table and then set the circuit board material on top of it. The moisture in the paper towel makes the entire apparatus much steadier which helps with drilling the islands; It also makes cleanup a snap.

[@w2aew]

Nice tip - I like it!

[@dancross2089]

Thanks! I love your videos and always come away from watching them feeling like I've learned a tremendous amount. 73 de AC2OI

[@urugulu1656]

thats actually similar to what professional Chefs do to avoid their cutting boards slip all over the place

[@JohnRaschedian]

This was a nice and interesting video! I have not built anything in about 30 years. I think I'll build something now. Thank you :)

[@JohnRaschedian]

I did actually start to build a power supply that I have been postponing for the last 4 months probably. Although you could get a second-hand professional power supply on Ebay for around $40, building it is a lot of fun. I thank you for the inspiration sir!

[@standishgeezer]

For those (like me) who don't have a drill press , take a piece of wood about 1/4" thick (and long enough to hold) and drill a hole in it about the size of your diamond hole cutter. Press the piece of wood on top of the copper clad board with the hole over the point you want to cut your island. You then have a guide through which you can pass the diamond cutter.

[@NewbergUSA]

Thanks for the excellent video example and explanation. Caused me to watch some of your other videos. Built the ckt and it works well with xtals in the 2.5-13mhz range. I wanted a 1mhz crystal calibrator and found I needed to change some values to get it to oscillate at 1mhz. Changed the 10k base to gnd to 6.8k. Changed 470pf B-E cap to .005uf. Changed 470pf Base to gnd to 820pf (a .001uf would probably work too). Works great. Now installed in a DX-160.

[@matthehat]

That nixie tube frequency counter is gorgeous!

[@w2aew]

Thanks - that's one of favorite pieces of equipment!

[@sidewinderam9m]

I used to painstakingly cut tracks in a circuit board with about a 3mm diameter diamond wheel bit but this looks way easier. Diamond holesaws can be purchased pretty cheap on eBay. Thanks for the video.

[@marcosbarros8069]

I've worked most of my life with crystal oscillators, but never came across such a handy construction style: Manhattan! Great, and thank you!

[@mheermance]

This was extremely helpful. I have been thinking about building some RF circuits and heard that Manhattan style construction was a good choice. So this was a good overview of the technique.

[@robertcalkjr.8325]

Thanks Alan! I am tired of Chinese companies locking MC's so that I can't save the data to program a new MC if for some reason the one in the device gets knocked out. So I built one of these Colpitts oscillator's to test crystals with! I have a whole bunch of 2N2222A's, so I used them. According to the datasheet, the 2222A has 50MHz higher transition frequency and 5pF less input capacitance than the 2222. It is working great!

[@zerovolt24]

It would be interesting to make a qualitative analysis of the performance as an oscillator by observing the shape of the trace on the oscilloscope and a measurement of the output power. I've built one (different capacitor values, 680pF) and crystals up to 9MHz show a distorted sinusoid, like the one you get, more or less, whereas with 12, 16 and 20MHz I get a practically perfect sinus shape.

[@cymeriandesigns]

This was great. I've been looking for a video that went thru the whole process of a Manhattan style circuit construction. Thanks so much for making it.

[@joepiscapo936]

Thanks dude...you will not be forgotten :o I got 3.57 mhz kind what you had, but 13.57 mgz came out as nice sine wave. on 9volt battery

[@delron44]

superb vid, was looking for a 6 mhz colpitts, worked first time, thank you for posting.

[@rogeronslow1498]

Nowadays I prototype with SMD components. You require a magnifier but with the correct proto board it's really quick and easy.

[@timothyfidler2088]

yes but even with a Protoboard you then need to wire off to something else - lslands or Veroboard in general to pick up leaded components.

[@chemicalvamp]

I have never seen anybody assemble a circuit board like this. Very cool, And for how old this video is, you must have had a serious camera.

[@FrozenHaxor]

Nice video, I think that 6MHz crystal actually had a punched mark on top of it, weird spot for such package.

[@tiffanymiller4820]

Mincraft

[@FrozenHaxor]

Tiffany Miller What?

[@C32-d5j]

yeah maybe they used the same machine that punches the thinner ones

[@Mulazim.]

You could remove the crystal and replace it with Varactor diode, so you can divide the frequency

[@byronwatkins2565]

I haven't seen this prototyping method before. I can see definite advantages since every node except ground is a star.

[@usuthu65]

These videos are outstanding. Excellent conversational teaching style. Question: I noticed that your oscillator waveform has some higher order products in it as you test the two crystals. Do you cover this topic in another one of your videos or was that a characteristic of the crystals you tested?

[@w2aew]

This is very typical of simple oscillators or this type - not so much due to the crystal, just the nature of the simple single-transistor oscillator circuit.

[@usuthu65]

Thanks! Thought it useful to have that in the comments record here in case others noticed it. I'll go read more on oscillator harmonics.

[@jlfqam]

Thanks for the schematics. It worked well. Some of the crystals showed nice and other distorted sine waves. I managed to rip off the protective canister using an iron file, sharp wire cutters and a thin flat screw driver, as can openers. Aiming a 5mW red laser pointer beam (with laser class glasses protection) on the bare crystal turned the output signal unstable without changing the basic waveform. Also tested resonators, some of which produce square waves, and managed to open the can on one of the miniature oscillators in HC 49S packages to see how nice and delicate is the crystal.

[@Satchmoeddie]

Hmm? So that is the Manhattan style? Okay then, interesting, and quite effective. Not quite as crude as "dead bug style". I was etching boards with ferrichloride when I was about 10 years old. Any lacquer based marker makes a resist pen for the etching fluid. The "Industrial" Sharpie is one that works really well, and for RF shielding dead copper / large ground planes, just brush on some lacquer paint. My first hand rendered through hole PCB artwork, taken from a schematic, for etching was the Fender fuzz wah/volume & tone pedal for guitar. It had an op amp, or two, and a couple transistors, & all the passive stuff. Not a great choice, but it works, more or less. The combination rocker & twist pedal case proved impossible to locate or build without some difficulty.. My very first PCB was taken off a photocopy, of the PCB traces & pads. It was a bootleg pay television descrambler. I used dry transfers on it. What a tedious pain in the neck, only lower! 73 KI7AQJ

[@EdEditz]

Oh those descrambler circuits. They never worked.

[@N2GJ]

Probably a dumb question: What do you mean by an "isolate node?" I don't know how you got 7...I've never been good at reading schematics, but I can stuff the right parts in a PC board pretty well....

[@w2aew]

"Isolated nodes" are the various junctions between components. Some of the components are connected to ground on one end, and connected to other components at the other end. It's these non-grounded connections that are "isolated" from ground, which is why I referred to them as isolated nodes.

[@N2GJ]

***** Thank you, Alan! Great video - what a neat setup you have (neat as in very cool rather than tidy!) Very interesting and informative as always. I am in awe that you can just look at a circuit like that and say "Oh, this is going to be 5.4 volts here, and this will be .7 of a volt lower...etc." I have no freaking idea how that calculation is done. I might have known at some point, but, as my friend Gary Wilson K2GW says, "Gerry is a No-Tech Code Extra!" That's what you are when you can copy Morse Code at 25+ wpm but would be hard pressed to do those calculations you do in your head! 73 and God Bless You and Nancy in the New Year! 73/88 DE N2GJ

[@acestudioscouk-Ace-G0ACE]

Really useful video thank-you. Rarely can you see a video which takes you through all the stages from schematic to function. Great!

[@rickvia8435]

Great stuff. Just a tiny bit of crossover on the + side.

[@alijabari8715]

what an interesting methode! every time I come here I learn new things from you thank you for sharing these things :)

[@Gary-vo9rm]

I became disinterested when you didn't identify the components. Who cares to watch you cut a blank of copper?

[@Tom-q9h7l]

This is typicial american BULL SH1T

[@bobkozlarekwa2sqq59]

Ordered the cutter. Tried three different pcb materials. The cutter removes the entire dot. I’m also seeing that the removed copper remains in the cutter. What’s the trick?

[@w2aew]

Try using very easy/light pressure with the drill press - just ease into it, don't bear down. Little touch-and-release moves.

[@DarrenLandrum]

Do you buy your boards with single-side or double-side cladding? I'm thinking about building a (relatively) simple analog synthesizer, and I want to use single-clad board with the circuit on one side and the front panel on the other. Thanks!

[@w2aew]

Typically - I pick up whatever I can find cheap! Usually, it is double side cladding, which is good for the RF circuits I make. You could use double sided for your project - just polish up the copper with steel wool, sandpaper, etc. and coat it with urethane and it will make a nice brushed copper metal finish to your front panel.

[@DarrenLandrum]

Ah, I was thinking of going single-sided and then painting the unclad side, but that's not a bad idea either. :) Thanks!

[@subhasarkar8823]

Nice method. Will try to follow this neat and clear way of circuit build. I feel this method has significant lower parasitics than breadboard.

[@jonbonne]

excellent video, i really enjoyed it! i've only utilized the toner transfer etching method, but i really like the simplicity/minimalist approach to this prototyping model. i want to try it asap.

[@acmefixer1]

Nice clean assembly & test. I noticed the waveform isn't quite symmetrical. Is that because the xtal is overdriving? I would have put a DC blocking cap between the socket and base. This allows testing parallel resonant tank circuits without shorting the base bias to ground.

[@alnoorratansi9364]

can you use this circuit to 32khz crystals? what range of crystals can this circuit be used.

[@w2aew]

It should, although you may need to increase the 470pF caps to something like 4.7nF.

[@stoneslice]

Great tutorial. Thanks, as always. I would like to see an identical circuit built with various construction methods, then check the output of each for differences. i.e breadboard capacitance effects etc. I would like to do this myself, but my test equipment is not up to yours for spec. Thaks again Stoneslice.

[@DeeegerD]

You can get a diamond hole cutter from Lee Valley that should be perfect for this. Search for "Diamond Hole Saws". Could be used in a drill press or with a Dremel rotary tool as it has a 1/8" shaft. (1/4" hole x 1/8" depth). Under $10 Cdn.

[@DeeegerD]

+Digger D I was also able to find the diamond hole cutters on eBay. Just ordered 2, 8mm diameter ones for under $3 US. This type is more of a tube bit.

[@caraquedesafiouopapaco2511]

This ocilator can hold a 32khz cristal?

[@chasihler]

Entertaining video Alan; how do you cut your PCBs so nice? Assuming you haven't bought a grab bag of small cut boards ?

[@w2aew]

In this case, I did obtain a small pile of small PCBs (from QRPme as part of their Manhattan Chowder kit). But, I've had good success wil a few methods like: scoring both sides with a knife and breaking, using tin snips, using a a jig saw, etc.

[@milesprower6641]

mmm... thoes bearing on the drill press might need to be referbed/replaced >.

[@w2aew]

Yeah, they're older than I am.

[@workout74]

sorry i mean where do you get that type of bit, and what is it called? wb2ecl

[@w2aew]

See the links in the video description. The island cutter was purchased from QRPme.com

[@KubuntuYou]

I can honestly say I've never seen this prototyping style before. So easy to soo where everything connects.

[@FullElectronic]

What's the range of frequencies in this case? for example using two 2n2222...

[@opablo_gm]

Great video as usual... Sorry if this is a basic question but... What would be the easy/simple way to "clean-up" that output wave ? I guess it's not about applying a LPF because it should work on any freq... maybe you need to make another nice-sine oscilator and "drive it" with the first dirty oscilator in order to get only the fundamental freq ? (I'm not an EE... just an Amateur trying to take a guess here)

[@w2aew]

A low pass filter or tuned circuit load that only passes the fundamental would clean up the output. Of course, the design of the filter/load will be dependent on the crystal frequency being used.

[@stormtrooperelite1453]

3.57 eh? Not great, not terrible

[@t1d100]

This video does a good job of explaining how the component values are calculated and why they matter: kzbin.info/www/bejne/f2XFcpl6qpt5Z80

[@vladgladkikh]

Will it also determine the resonant frequency of a piezoelectric diaphragm (buzzer). I tried, it didn't, even though I put larger capacitors because its resonant frequency must be around 10kHz. Maybe I am doing something wrong with the circuit, or is there a fundamental difference between quartz resonators and piezo buzzers? How to modify this circuit for measuring the resonant frequency of a piezo buzzer?

[@ryancl03]

img.photobucket.com/albums/v230/ryan_03/20160713_2316021_zpsqo8pu1e0.jpg built on a vero board with smd components.. works great!

[@TheOldcoder]

Do I need a frequency counter to test a circuit like this, or would my digital oscilloscope do the job? (it does show frequency in measurement mode as well as pp voltage etc)

[@w2aew]

The scope will be perfectly fine. A counter will give you a more accurate frequency measurement than the scope, but the scope is certainly sufficient. Of course, you can also see the signal quality and amplitude on the scope - these are things that the counter won't do for you of course.

[@DantalionNl]

hi ***** great video, I had one quick question, The transistor needs to be fast enough for the crystal right? should I get a specific one to rebuild this or do you think most transistors will do just fine.

[@timothyfidler2088]

The transistors suggested are written on the paperwork near the osc design. In general you will need a transistor with a transition freq, Ft at least twice the desired osc frequency in order to be sure the osc. will start. In fact the true start conditions are a little more complex than that and they are tabulated in old TI semi books for Hartley and Colpitts designs especially. Audio transistors simply will not work in this circuit -they have too much input capacitance and too much capacitance from the base to the emitter lead. One transistor that simply shines for Osc duty is the BSX-20. You may be able to get it from Futurlec.com . In Oztralia , Rockby in Melb used to have stocks. It has a metal case so it keeps cooler when driven hard and the Ft is about three times better than the generic 2N 2222. Datasheet njsemi.com/datasheets/BSX20.pdf. If you have some marginal microprocessor grade xtal and the circuit will not osc with a 2N2222, then putting in a BSX-20 will often make the difference, esp between about 16 Mhz and thirty Mhz.

[@ernieschatz3783]

@@timothyfidler2088 Ft =Tf= fall time, or is that fault tolerance?

[@timothyfidler2088]

@@ernieschatz3783 Ft is the frequency where the transistor''s current gain is equal to zero. Obviously this statement is simplistic as current gain means something only when the topology , eg common emitter , is known . Therefore the Ft for a given part from a given mafr is defined by his measuring circuit topology and this will be detailed on his datasheet, one hopes. There is more detail on this in Wikipedia under gain-bandwidth product en.wikipedia.org/wiki/Gain%E2%80%93bandwidth_product. This article suffers from some crappy editing - omega C is not defined but it appears to be the - 3dB drop angular frequency for a given op amp (in which case the Gain BW product is defined in terms of voltage gain).

[@timothyfidler2088]

@@ernieschatz3783 you might like to modify this circuit slightly to work with a J310 nFET (which works at VHF). The bottom 10 K bias resistor on the first transistor increases to say 25K ohm. The upper one disappears. You also had in s small signal diode across the new bias resistor to GND to soft clip the RF going to the gate of the FET ; this then fixes the magnitude of the amplification. BTW the 470 p capacitors produce an impedance transformer effect from the 1K emitter resistor of TR1 back to the base circuit of TR1. Such a circuit will be more repeatable. You might find TR2 , the OP transistor has to change to a high gain transistor like an MPSH10, because the FET will need to see a higher input impedance as its load. (might find etc - these things are calculable or can be tested/trimmed up by simulation on LTSpice, which you can download from Linear technology ) There are only a few places to go for RF parts at a reasonable price nowadays but you can try Cecil the Parts place (do a google search on it) - he also sells magnetic components such as toroids and pignose baluns which are useful for RF transformers. There is or used to be a whole PDF of interesting AF and RF experiments by Todd , a Canuk ham. qrp-popcorn.blogspot.com/p/blog-page_9.html then go to the download link, not the NT7S Blog - of course quarantine anything you get and virus check it (I would but there was no virus). It is just one big PDF of all sorts of experiments and theory. Every circuit is illustrated with a point to point wired PCB so you can trust, to an extent, that he built the damn thing. You will find JFET bias, RF power amps .. all covered there one way or t'other.

[@1903A3shooter]

Great Fun, it worked the first time, it was easy, I learned a bit more and I did not burn my fingers. Thanks, Dave

[@CantThinkOfAName534]

Do you have a video or know where I can find info on how engineers know where to place what components when designing? I have formal training in troubleshooting circuits but it’s always baffled me how engineers know where to put everything.

[@colt4667]

This is probably a dumb question but lemme ask anyway: when designing a ccircuit how do you know when to use electrolytic or tantalun or some other kind of capacitor?

[@w2aew]

Not a dumb question... ...the choice of capacitor type is usually dictated by the application and value. If the application required a large capacitance value, then that will usually mean electrolytic or tantalum. If low ESR is needed, then a tantalum would be used. If cost is the driving factor, then an aluminum electrolytic might be chosen. If the value is small, then it could be a multi-layer ceramic cap. If low leakage is important, then it would probably be a film cap. It all depends on the application...

[@purza95]

+w2aew What is "ESR"?

[@w2aew]

+purza95 ESR = Equivalent Series Resistance

[@LEDbulbumr5571]

I think this is the one of the best KZbin video channel for radio amateurs best 73s AP2GA

[@Tom-q9h7l]

Rather the worst...

[@JamesCutlervk2tim]

Good video - but DC into a crystal is never a good idea.......it will work, but not forever.....

[@OM0ET]

Good idea to do circuits with "Islands style" fashion! :-) thank you. 73

[@vishnudas9476]

Can this circuit be biult ordinary perfboard ? Any reason for using copper clad instead of perfboard ?

[@TheLightningStalker]

What do you think about using the bottom as +Vcc on a 2 layer board? It would even add a few pF of filtering to the supply.

[@w2aew]

Yes, you can do that. Often times, VCC are plane layers in a multi-layer board. In this case, you just have to take care not to short VCC to anything (chassis, etc.).

[@alidapaunic5587]

Can you tell if this work for 6 or 10 different christals or we need for each christal another plate what is calculation sheme for ten christal do you know that

[@bblod4896]

Built the oscillator on a prototype board, did not have the exact NPN transistors and did not have 470pf caps. I used 330pf caps. Tried a 5 MHz crystal and it worked but the sine wave is not pretty. I ordered some 470pf caps And the recommended transistors. I have a 27.185 MHz CB crystal. I want to build a test oscillator to check the receive of CB transceivers. When I used that crystal, the oscillator had issues. Should I assume the 470pf caps help in cleaning up the sine wave?

[@Sixta16]

why do I think this circuits extremely capacitively overloads the crystal? (the two 470p accross the element)

[@HansVanIngelgom]

Funny, just days ago I made a post about the crystal oscillator I made while studying for my ham exam. It's a great circuit for that purpose. This time you missed an opportunity to have an aha!-moment for your viewers though: you should at one point have used an LC-circuit instead of a crystal. But maybe that would have lead to unwanted digression. For reference, this is a post to my article: hansvi.be/wordpress/?p=25 Best wishes for 2014.

[@gokhanpala]

Is the capacitor value there 120pF? Would you answer urgently? Thank you.

[@w2aew]

No. The capacitor values are clearly marked in the schematic. Very readable at the 1:00 point. For frequencies above 10-15MHz, you may want to lower the value of the two 470pF caps to 100 or 150pF each.

[@drtidrow]

Gotta be careful with the transistors, though, as many of them are emitter-collector-base instead of emitter-base-collector. IIRC, even the same type of transistor (eg. 3904) can have different pinouts from different manufacturers.

[@michaelisbaldnow6063]

very cool video, I enjoyed it. I wonder if archaeologists in the future will have an eternally open question in their field regarding the discovery of vast quantities of 3.57954MHz crystals. I imagine it would seem random to them

[@Elec-DIY]

It works fine, although the output amplitude seems to diminish a lot with frequency, for a 8MHz crystal I get around 2 volts peak, for a 16Mhz I get 450mV peak, and for 20MHz I get around 100-200mV peak, maybe it needs an amplifying stage. I also tried with some crystals in the kilohertz range taken from alarm clocks but they don't appear to work. imgur.com/a/912bP PS: I know the 10nF capacitor is missing after the 100Ohm resistor, I added it afterwards.

[@w2aew]

All sounds normal. It's difficult to make a simple oscillator that works well over decades of frequency, without changing any components. For lower frequencies, the two 470pF caps would likely have to be increased - and you would probably want to decrease them for higher frequency applications. Your probe will also load the circuit and make the amplitude drop vs. frequency. A buffer would be an excellent addition.

[@Elec-DIY]

Many thanks. I checked with a 4MHz resonator and the amplitude is the same as yours. This is my first circuit involving frequencies higher than 100kHz, but I plan to try and make more high frequency and RF stuff, it's really interesting. Thanks again for your videos, they're great!

[@DoRC]

Awesome work. It would be really cool to have an island cutter that also drilled a through hole in the center. That way you could just stick the leads through and solder them up trimming afterward. With a double sided board you could even use a combination of drilled and not drilled to make the back side a power plane..... Maybe

[@DoRC]

I'm picturing three bits. One that makes just the island, on that makes island with through hole for connecting multiple things together also to power and one that strips the island away with through hole for single power with no other connections. A double Manhattan! (I have no Idea what I'm talking about btw:)

[@w2aew]

You could probably do this with a traditional brad-point bit. They typically have a pointed lead-in and cut the perimeter shortly after that. Even if the lead-in doesn't go through, you would have a starter hole to run a second small bit through for the lead hole.

[@tubeDude48]

What's that bit called?

[@SeAfasia]

Ηi Alan, I assembly this schematic and I'm going to test it soon.. Regards..

[@copernicus633]

I love his presentation-so to the point, without a lot of irrelevant chatter.

[@pilobond]

This was first circuit I made on a copper-clad board a few weeks ago. I just wanted to report that it works as you describe. I couldn't find the island cutter, so I tried "lipped brad-point drill bit" ( www.leevalley.com/en-ca/shop/tools/power-tool-accessories/drill-bits/42247-hss-lipped-imperial-brad-point-drills ) I used 1/4" one and it seems about the right size. It also leaves a hole in the middle where I can insert a component lead to hold it there :) de VA3GPJ

[@Qqq-s9k]

Hi Alan, I tried to run on 72.310MHz quartz, and it's executed at a frequency of 12.5. As known quartz can only operate at odd harmonics. Why could it happen?

[@minazulkhan8287]

hi..its a nice video ..what is peak to peak voltage of op waveform and what if i use 40mhz crystall..will peak to peak change ?? and also can u suggest method to amplify op

[@FullElectronic]

Good very good, i can use this to prove XTALs naturally...

[@nunogue]

This case caught my attention because i had a bunch of unmarked chrystals lying arround and i didn´t even knew if they would work or not. So i built the oscillator. I didn't use the island cutter method (used a common prototyping board) but i found the method and your expanations extremely good. Probably i´ll give it a go in the future. Anyway, in the end i found out that a lot of those chrystals i had didn´t work, even some marked ones... It was a lot of fun and useful stuff. All this to say: Thanks.

[@hunt555fish]

What frequency range of crystal oscillators will this test?Nice job on the build.I need to find my pad cutter tool I used years ago.Guess If I have to I can cut pads and glue to the copper board.

[@w2aew]

This would be usable up to several MHz. For higher, the capacitor values would need to be dropped.

[@owenvinall9970]

Thanks very useful video. Cant wait to try this.

[@SeAfasia]

Hi Alan, I build this as an ugly construction,works fine with good stability,keep the same components values like you and test it with different crystal values.The Sin Waves are accurate every time change the values.. Only,when I testing a crystal,with values 21.000 MHZ and 38.000 MHZ I don't get a Sin Wave,is there a limit at MHZ on circuit?I'm going to using it as a simple crystal tester... Regards Kostas..

[@w2aew]

You will probably want to lower the two 470pF capacitor for higher frequency operation - try a pair of 180pF for example.

[@SeAfasia]

***** thanks, I'm going to adding two variable capacitors up 120 pf both...

[@nodriveknowitall702]

I know I should mind my own business but you should really keep your hands free from hazard and clamp that pcb when using the drill press.

[@bumohamedubualooy7111]

what is the use of the upper 10 nf cap below the 100 ohm resistor? decoupling or ac ground to prevent signal loss in vcc? the 100 ohm to make the path more resistive to high frequency? or just for the biasing scheme?

[@w2aew]

The 100ohm and 10nF cap provide AC isolation from the main power source. It keeps any noise from the power supply from getting into the circuit, and prevents the circuit from injecting too much noise on the power supply.

[@leoj.nesuahecner1242]

I don't understand...it looks like you are cutting circles in the copper thus isolating it from the larger area which is ground. I get that but it sure looks like the solder is breaking out of the circles or islands and touching the ground plane. How do you avoid that?

[@carmelpule6954]

Due to surface tension of the molten solder, it does not cross over out from the circle. just leave the tip of the soldering iron on the circle and do not let the tip bridge the gap. It is easy with a little bit of practice.

[@colt4667]

Nice video. I've not seen this island method circuit construction before. I'm subscribin.

[@au7weeng534]

I use an island cutter with a center pin I made from a flathead bit (just filed two slots into it and sharpened the edges.) The pin goes into holes I pre-drill. It's self-centering and one doesn't need a drill press

A technique to make islands could be to make a midway through hole and then bend in a circular way the drill that will do the job.

[@chent]

Nice, I like the way you build that circut, I will try to aply tha method to something :)

[@cokabs]

HI, i have the same frequency counter, LDC-821S. Great Japan tube display instrument! Great channel, cheers from Uruguay.

[@lynnhancock8641]

I tried this today and it worked great and it was fast! I glued little squares of copper-clad for islands but going to buy a rotary spot welder cutter bit from Harbor Freight tomorrow. Was able to check out several unlabeled crystals.

[@bakupcpu]

Very nice tutorial Thanks!!! those lovely unmark crystal haha.....got that on cap and inductor the joy :)

[@shadowshop1]

hi i use a small model mill to cut the tracks on the copper boards i plan the tracks on my computer first i like this video big time very use full tips

[@aqib2000]

What is your PCB holder called so one can search ebay for something that stable

[@arnelpasiona5136]

iam use 27 mhz crystal and add to one 4 stages transistor .and out pot at 108 mhz frequency...

[@w2aew]

+Rocky Nel If the output is not an exact multiple of the crystal frequency, then you've got some kind of parasitic oscillation happening - usually layout related.

[@RiverWyvrn]

Is it safe to add untinned component leads to lands that have already been soldered without adding any extra flux or solder? Don't you get problems with the old solder not wetting to the new lead?

[@w2aew]

Most of the component leads are already tinned, so it isn't a problem. If the leads aren't tinned, then I'll usually pre-tin them before soldering. If I have a problem with wetting, then I'll apply flux.

[@GeorgeTsiros]

OH SHIT THAT COUNTER LOOKS DELICIOUS ahem, sorry. Got a bit too excited there. Interesting piece of equipment, the nixie tubes (that's what they are, right?) really look nice in it.

[@w2aew]

+George Tsiros Yes, I love that old Nixie tube counter.

[@Satchmoeddie]

+w2aew I found a stash of about 4000 Nixies that were supposed to be used at Palo Verde Nuclear Generating Station. In the 10+ years it took to build the plant, technology changed, and the numerical indicators became 7 segment LEDs or custom VFD displays. As time progressed, more CRTs, then LCD flat screens, and back to LEDs only in a flat screen format. No more Nixies, though. Those Nixies all wound up in a surplus electronics, electrical, mechanical, misc. and ??? shop. When it comes to the analog stuff, a D'Arsnoval movements will stay the same, a Magnahelic, will always be a Magnahelic, a Photohelic will always be a Photohelic, pressure gauges will be pressure gauges, & sight glasses will be sight glasses. Alas, no more Nixies.

[@GeorgeTsiros]

Seth B so uh... what did you do with them?

[@billwilliams6338]

W2AEW, for non-RF boards, just TTL digital boards in the 80's when using an oscilloscope to measure the crystals waveform and frequency it would change because the inductance & capacitance of the Oscilloscope probe would affect the readings. If the crystal was 4Mhz the Oscope probe would change the crystals frequency to be other than 4Mhz, any reasons how to prevent this from happening?

[@w2aew]

Since the crystal is used to make an oscillator, don't probe the crystal directly, but rather probe the output of oscillator or oscillator buffer.

[@billwilliams6338]

@@w2aew yes that is what I have been doing because you get different measurements of the oscillators frequency/clock frequency. I'm guessing because the clocks test point has circuit board trace capacitance and resistance from the output pin to the Clocks Test Point and also get a different clock frequency measurement when measuring from the oscillator output pin will measure the clock frequency I will get a different clock frequency measurement. It seems that the Oscilloscope probe has inductance and capacitance which is altering the clock frequency on the oscillators output pin and also on the circuit boards clock test point lug. Any reasons why?

[@ashokdas2070]

Thanks a lot for the video, i was inspired to create this circuit. It functions nicely, but i have one query. The output is not a pure sinewave, somewhat distorted. What step can i take to make the output smooth ?

[@w2aew]

Simple oscillators like this have a lot of harmonic distortion. The best thing to do is to use a low-pass filter on the output or use a tuned amplifier on the output.

[@ashokdas2070]

@@w2aew I was also thinking something similar to use. You have now confirmed it. Thanks again for the reply. I really appreciate your efforts to support DYI community.

[@minazulkhan8287]

hi ...plz tell waht is peak to peak op of this ckt ......and will p to p will be same if crystall is of 40 mhz

[@stargazer7644]

@@minazulkhan8287 He shows you the scope that is probing the output. It shows the signal output is about 5V p-p. The transistor will lose gain as the frequency increases, so the level will be less at higher frequencies. You'll need to make sure your transistor will work at 40 MHz, and you may need to use lower value capacitors.

[@bobmiller38]

How would you calculate the impedance at the output cap?

[@andrewferg8737]

Could you explain a practical way of multiplying the crystal frequency?

[@w2aew]

Some crystals can be made to oscillate at upper harmonics.

[@andrewferg8737]

@@w2aew Stupid Question: Can you use a tuned transformer to multiply the crystal frequency or will the crystal overpower the tank circuits?

[@stevec5000]

I've got an old Lafayette model HA800 short wave radio that is dual conversion with 455 Kc and 2.608 Mhz IF's that quit working after some parts in it's 2.153 Mhz second osc. drifted off freq. It's a Colpitts osc. like the one you used in the video so I built it up on a bread board to get it working but I found that some of the parts values they originally used wouldn't work so I put some new parts in and mounted it back on the radio's PC board. The problem I'm having now is that since the output is not a sine wave but more like a saw tooth similar to the one you showed, I get tons of harmonics all across the dial! Do you know if there is a way to get a better sine wave out of this circuit? Thanks.

[@w2aew]

The most popular ways to get lower harmonic distortion with simple oscillators like this are: - Use a low pass filter on the output - Use a tuned-circuit load in the collector - Tweak the gain of the circuit to be just enough to sustain oscillation

[@stevec5000]

@@w2aew Thanks, I'll try that. Oddly the radio did have a tuned circuit across the oscillator but the parts values are way too small and it is resonant at 15 Mhz instead of 2.153 so it needs a larger coil to make it work. The radio seems more like a science fair experiment than a commercial product but I guess that's why they came out with a version A then a B!

[@gfr2023]

13:20 a nixie display frequency counter ??? this is really cool !!!

[@shvideo1]

Excellent video and test circuit. Thank you for putting this video together.

[@bblod4896]

By the way, I priced the book you mentioned in this video... rather expensive. Will have to wait on that.