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This is a basic tutorial on PIN Diodes, with some examples of how they are used in RF switch applications. I previously published a video that introduced the topic of how diodes can be used as switches:
• #82: How to use a Diod...
This video takes this a step further, discussing the unique characteristics of PIN diodes and how these characteristics are used for switching large RF signals. The unique ability to have the resistance of the diode be adjusted by changing the bias current can be used for other applications such as variable attenuators, modulators, phase shifters, etc.
In the video I state that PIN diodes aren't suitable for fast switches. What I should have said is that PIN diodes aren't suitable in applications that require fast turn-off characteristics when reversed biased - such as rectifier, detector or mixer applications. PIN diodes do make excellent fast (relatively speaking) RF switches.
Here's a followup video showing some 3rd order IMD measurements vs. bias:
• #130: PIN Diode 3rd or...
The Yaesu FT-7800 Repair Log videos that inspired this tutorial:
Part 1: • #116: Repair Log, Part...
Part 2: • #117: Repair Log, Part...
A copy of the notes in this video can be found here:
www.qsl.net/w/w...

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28 сен 2024

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Комментарии : 285

@picwiz2 6 лет назад

You are simply GREAT: a GREAT teacher in a GREAT lab. TNX!

@gerrysweeney 11 лет назад

Hi Alan, another great education piece, I always learn something new when I watch your tutorials - thank you.

@muniswamy100 2 года назад

This is how you understand electronics. This stuff is worth hours of meticulous reading from books. Thank you!

@haroldtorres4228 7 лет назад

Wow. I really enjoy and learn from your teaçhing. We're house electronics teacher before. I haven't seen a teacher demonstrate theory and show the test like you do.I once had a excellent teacher back in high school who thought me well but you are awesome. Keep up the excellent job. You have a teaching gift. I am getting baçk into electronics. Your teaçhing really helps. God bless you buddy.

@w2aew 7 лет назад

Thank you - I am glad you enjoy my videos!

@doctordhd Год назад

I watched this again and learned even more. Thank you.

@tunicana 11 лет назад

Very interesting tutorials, now i love more and more your vids, especially RF stuffs. Thx Alan

@kevinbyrne4538 10 лет назад

The oscilloscope displays of the phenomena being discussed are very helpful. Many thanks for taking the time and trouble to prepare and post these videos.

@Lyndon_K Год назад

A great explanation of the PIN diode. Thank you so much!

@kao354 3 года назад

Excellent! Believe me, as I have > decade of teaching experience, you are just great!

@thomasschmidt5546 2 месяца назад

Thank you very much for your excellent done videos. This is the kind of learning i love, by practise step by step testing seein the result and readjust to see whats result after chaning. Great done!!! all the best

@hectorpascal 5 лет назад

Excellent tutorial! I have advised my Uni students to view it.

@friedmule5403 4 года назад

You know sometimes you just find the right video, made by the right person, and everything just goes up to an other level, that's what I have experienced several times on your channel, including this video! :-)

@gsansoucie 4 года назад

Excellent video. I’ve come to love my Elecraft rigs and the quiet nature of my HR 50 ATU with the QSK board, but I never really understood how PIN diodes worked and certainly not how they worked in place of relays (such as the noisy ones in my IC 7300). I understand the mechanical nature of the the relays, but never understood the complexity of the PIN diodes. Now I know, thanks for yet another awesome video. De W1ND.

@smgvbest 7 лет назад

I was looking for a good explanation of how pin diodes are used as switches and this helped allot. thank you

@robertcalkjr.8325 9 лет назад

Thanks Alan. That's interesting. All the times I bought all kinds of diodes, I don't remember ever seeing any PIN Diodes.

@madhirasriharsha 4 года назад

I never thought much about the TR switch as explained in the video.. really nice video, thanks for sharing all these insights.

@michaelhawthorne8696 10 лет назад

Great video Alan. I wasn't aware of these diodes and didn't know about the 1/4 wavelength property of inverse impedance, ingenious way to chose between Tx and Rx using minimal components.

@basinstreetdesign5206 6 лет назад

Thank you for this. I now know that I understood little about how PIN diodes behave.

@k8axw142 11 лет назад

Alan: Thank you very much for this video on the PIN diode. Many questions answered!! I never encountered PIN diodes until I built a 40M transceiver which uses them. When I went to trouble shoot the circuit I saw just how far behind I've become in the electronic field! Again, thanks for the tutorial. As usual, one of excellent quality!! Al - K8AXW

@decarr66 3 года назад

This is an excellent primer on using PIN diodes in RF switching applications!

@n4mjf2a 7 лет назад

Thanks. Enjoyed the video very much. My goal was to learn how PIN Diodes work and you made it quick and simple. Good show.

@JanCiger 11 лет назад

Thanks for the video! I knew about diode switching, but I didn't understand how it could work for large voltages, such as in transmitters or various antenna switchers, not being aware of the "storage bucket/flywheel" characteristics of the PIN diodes. Cool, I have learned something new! BTW, you have a really excellent drawing style - my computer drawn schematics and diagrams often don't look as good as your hand drawn ones!

@ankur1888 5 лет назад

Thanks from India! Your videos are great!

@mikelaspina7670 6 лет назад

Thanks, clear, concise and paced perfectly.

@binfoon 9 лет назад

Your videos are very well presented and are informative. You make an excellent teacher.Great job, Thanks for your presentations.

@va3ux 6 лет назад

Thank you ! That was excellent. I think I now have at least some understanding of what I am looking at in the front end of my TS-930 schematic. ie. Switching of the bandpass filters. This video 'solved' it for me.

@SivaranjanGoswami 9 лет назад

Really nice... Well explained with both theory and practical ..Thank you for such a great lesson..

@nickwood4367 2 года назад

This was really helpful Alan. Thank you so much.

@squee222 6 лет назад

Best video. Thank you. I need to do a presentation on these diodes for school. This really helped.

@w2aew 6 лет назад

Glad to help! Let me know how your presentation goes.

@FamilienSoelberg 11 лет назад

Yet another fantastic video. Awesome explanation!

@egbertgroot2737 4 года назад

Very useful ...now i know why my diode bridge in secondary ruines the MOSFETS in the switching power supply.....

@Rob-du9ui 6 лет назад

Many thanks for the information. Very clear and concise.

@byronwatkins2565 3 года назад

The intrinsic region is neutral; it stores no charge. p and n carriers diffuse into the intrinsic region and recombine. The diffusing p carriers leave behind a negative charge layer in the p material and the diffusing n carriers leave behind a positive charge layer in the n material. These charges generate an electric field across the junction that balances the increase in entropy from diffusion. The larger plate separation REDUCES the capacitance and accumulated plate charge (Q=CV) relative to a pn junction. Additionally, the increased junction volume greatly increases the probability that a photon will ionize a p-n charge pair before passing through the volume.

@n5xnq 9 лет назад

Thank you for the great video tutorial series! I have a question regarding TX/RX switching and ¼ wave transmission line. I have looked at various pin diode circuits for the VHF band and it appears that most circuits deal with the ¼ wave transmission line by adding 2 capacitors on each side of an inductor coil. I wanted to see if you could explain how to calculate the values to use?

@w2aew 9 лет назад

You simple calculate the L and C values that have a Xl and Xc equal to the line impedance at the desired frequency. L =50/2piF and C=1/(2piF*50)

@n5xnq 9 лет назад

***** Thank you for the information.

@w2aew 9 лет назад

n5xnq I think you'll like my newest video: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-A1BAq0KxIdc.html

@seekinggod3174 4 года назад

Great tutorial Alan as always!

@PapasDino 11 лет назад

Super job Alan! 73 - Dino KL0S

@omsingharjit 2 года назад

Does it gives high capacitance value if it be use as Varicap ? Because of high charges storage capabilities ?

@ricardonunes6724 8 лет назад

Thank you for the very educational videos! I have one question... Why doesn't the diode turn on when the signal is in the positive half cycle? Is it because it also doesn't have time to charge the "bucket" and because of that remains off? Thank you!

@w2aew 8 лет назад

+Ricardo Nunes The DC bias used in the "off" state is usually set large enough to keep the diode from turning on during the positive half cycle peak.

@omsingharjit 2 года назад

13:09 So , Although it has ony two Pins If it act like Transistor switch linearly respect to the Bis current, can it be also use as Amplifier like instead of fix current bise what if i place signal current to its bise !? Will it linearly Amplifi the input signal ?

@tladilebohang 3 года назад

Do you have a video on rf switches using BF998

@w2aew 3 года назад

no, I don't have any videos showing RF switching with MOSFETs. Just a video on the basics of FETs in general.

@bakupcpu 11 лет назад

Thanks for this little video I was not aware of those diode :) Now I am lol Cheers!

@tHaH4x0r 10 лет назад

Very intersting video, i have made a diode switch before with a normal diode, but i was unaware that there were special diodes available that work much better. Where would such a diode switch be positioned in a RX/TX RF circuit? I take that if such a switch is used to switch between transmitting and receiving, would it be positioned to to turn on (pass the signal) when transmitting, or to turn on to pass a signal when receiving?

@tHaH4x0r 10 лет назад

Wops, did not see the video entirerly, diregard my comment since it was already answered in the video!

@ksrele 11 лет назад

Very nice video. I love your videos about RF, they are very understandable for begginers. My I ask you to explain one situation for me? Why do FM radio recivers pick up signal from nearby (powerfull) FM transmiter on all frequencies not only on frenquency that is registered to? For example FM transmiter is emiting on 100MHz but with (basic chipy) reciver I can hear program all around the scale (where is no other stations). You can make video of this or just answer me via reply to comment or in PM. Thank you.

@busterzz 7 лет назад

Can you do a video on SPDT or SP3T with PIN diodes? Excellent video btw.

@GregoryCharvat 11 лет назад

Excellent Demo!

@vex9060 11 лет назад

Really appreciate this video and your explanations on this topic. 73s

@Gameboygenius 11 лет назад

It would have been interesting to see the signal without the output filter cap, so you could see the DC level compared to the waveform distotion more clearly.

@waynegram8907 3 года назад

What are some examples when circuits are using "steering diodes"?

@emm1257 3 года назад

Hello Alan, first of all great video! I have a question about the inductor after the bias input. Why is it needed? To keep the high frequency signal from taking the bias path, e.g. a high resistance for the AC? Thank you again for the video!

@w2aew 3 года назад

Yes, precisely. The bias source is typically a low impedance, so would attenuate the AC signal if not blocked from it. Also, prevents the possibility of the AC signal from coupling on the bias source, and then possibly feeding into other circuits.

@hamradio323 6 лет назад

Hi i realy loved your vid of pin diodes thums up! Tnx.

@toddanderson1506 9 лет назад

Great video, thanks! I would like to learn more about pin diodes in AM modulator circuits. Do you have any videos explaining how this works? I would appreciate any information you can give me. Thanks

@964tractorboy 11 лет назад

Very useful information and good style, thanks. I expected some kind of breadboard layout so the "custom" board surprised me. I can see the 50MHz signal would/could have been a problem for a BB. When do you have to go to a "custom" layout?

@w2aew 11 лет назад

I'd say once you're dealing with frequencies above a few MHz it's a good idea to start getting off of the plug-in breadboard. My "custom" board is nothing more than a hunk of double sided copper clad, with some "traces" made with an exacto knife.

@darrenolafson5266 11 лет назад

You mentioned that a pair of inductors would usually be used to bias the diode instead of the resistors. What is the benefit of using inductors?

@joblessalex 11 лет назад

I'm assuming that if you choke just a certain frequency, it will allow the diode to be biased only when there is RF, effectively eliminating the need to add it to a microcontroller or something. Don't quote me, just what I think.

@darrenolafson5266 11 лет назад

joblessalex I'm guessing it's because of the thermal noise of the resistor is unwanted.

@wxfreak 11 лет назад

Some resistance would be needed for current limiting, Inductors would help keep RF out of the control voltage circuit along with the bypass cap to ground.

@Gameboygenius 11 лет назад

Darren Olafson Thermal noise will do nothing in this case. The diode is fully on, and the minor amounts of thermal noise introduced by a resistor are insignificant. The reason, I would assume, is to prevent feeding the RF signal where it doesn't belong, ie into the circuit that is generating the control current.

@darrenolafson5266 11 лет назад

Gameboygenius I found the following in an Agilent appnote. "RF chokes (inductors) are used along the biasing paths to avoid RF signal leakage while allowing the DC signal to ﬂow through to bias the diodes. The RF choke must have adequately high impedance at low frequencies so that the RF signal will not leak through the biasing path leading to higher insertion loss."

@hoplit480 8 лет назад

Muchas Gracias, Is a excellent video.

@syscomweb1 10 лет назад

Excellent video , thanks for share.

@paritoshjoshi6886 9 лет назад

Nicely explained.

@RedMorningDawn 3 года назад

this is amazing thanks so much!

@ericvieira68 10 лет назад

Are there Power versions which can handle for ex. 10-20A of current? Could one use them instead of power Mosfets for high current switching power supplies (Mig/Tig Welders)?

@w2aew 10 лет назад

No, there are better devices for those applications (MOSFETs, etc.)

@dandearman2871 5 лет назад

Great job.

@schwinn434 4 года назад

@w2aew how practical is it to use quarter-wave transmission coaxial cable (I assume it standard coaxial cable, similar to cable TV cabling- not sure if 75 ohm or 50 ohm, by small electronic circuit standards be bulky) in a T/R switch application- wouldn't a particular length of coaxial cable only work for one particular frequency. Wouldn't the Series-Shut SPST configuration work for all frequencies - and offer just as much of a guarantee that the receiver wouldn't see radio energy from the transmitter?

@w2aew 4 года назад

At lower frequencies, the lumped element is much more compact than an actual hunk of cable. At higher frequencies, the cable is OK. There are a lot of ways to achieve the result. A series-shunt will work, but may not provide as much isolation since PIN diodes are perfect opens/shorts. Other configurations can provide more attenuation. This video was just to illustrate a clever design, taking advantage of the impedance inversion of the 1/4 wave line.

@schwinn434 4 года назад

Thank you @w2aew for answering my questions!

@rsocor01 9 лет назад

Hi. Can this technique be used to multiplex 13.56MHz antennas? I'm thinking about using 1.2mH inductors instead of the resistors. Do you recommend a better circuit for this purpose? Very nice tutorials. Nicely explained.

@w2aew 9 лет назад

rsocor01 Sure, it all depends on power levels, the amount of isolation needed, etc. If you chose to use inductors to bias the diodes, then you also need to take care of controlling/limiting the diode's forward current - so either bias through a current source or a series resistor.

@robinmidgett3347 3 года назад

I'd like to use a PIN diode to switch a 16MHz. signal on & off. Can you recommend a particular PIN diode, please? Through hole leads would be good but I can work with SMD as well.

@w2aew 3 года назад

Many of the distributors (such as Mouser) allow you sort the PIN diode selections by the minimum operating frequency. Here's a decent choice based on this search: www.mouser.com/ProductDetail/MACOM/MA4P4002B-402?qs=sGAEpiMZZMvzIsPcC61n6mK0VZ%2FmvpYcoLB1loinzPs%3D A decent article on PIN diode swithes: www.digikey.com/en/articles/how-and-why-to-use-pin-diodes-for-rf-switching

@robinmidgett3347 3 года назад

@@w2aew Thanks much for the quick response and additional info. At $30 each from Mouser, I'll have to keep looking for a more affordable component. I'm looking forward to getting this switch working in my project.

@w2aew 3 года назад

@@robinmidgett3347 Well then, this may be more up your alley: www.mouser.com/ProductDetail/Vishay-Semiconductors/BA479G-TR?qs=IenFidxwq1QW1OkLKReJow%3D%3D

@robinmidgett3347 3 года назад

@@w2aew Much more appealing...many thanks!

@shaanpatil1 8 лет назад

Really a Nice video. Thans a lot .

@shingtonshelby 6 лет назад

Hi..is it the same concept with AIGaAs Flip Chip PIN Diode?

@w2aew 6 лет назад

Yes.

@awaisahmadsiddiqi6505 6 месяцев назад

can a normal diode be used for that purpose?

@w2aew 6 месяцев назад

They can, but will generally not offer as much isolation (they'll have higher capacitance).

@naidudemudu5290 6 лет назад

Thanks Alan, Please guide me to select a PIN diode to switch 1.5KW pulsed power of 2% of duty cycle at 1GHz between two ports with an isolation of 35dB

@alanwolke6253 6 лет назад

I can’t provide a direct answer. I’d highly recommend asking the application engineers at the leading PIN diode manufacturers like Skyworks, Microsemi, MACOM, L3 Narda, etc. to get proper advice.

@barn5923 11 лет назад

Thanks very much very interesting give us more .

@maxberg9588 4 года назад

thank you!

@educatedmanholecoverbyrich8890 7 лет назад

Excellent. Thanks.

@gretalaube91 Месяц назад

Thanks for this lesson! Well done! I'm less stupid than before! 73 de W3IHM

@uccoskun 2 года назад

amazing.

@1959Berre 7 лет назад

Amazing

@faisgaffeimbecile1939 5 лет назад

Aged 15 or 16, I designed PiN diode-switching into a Plessey SL600-series IC based HF transceiver which worked essentially, and ended up being very similar to a renowned G3TSO design, though I never understood the 'charge-carrier-bucket' you describe so clearly. Excellent series of videos and amazed you take the time to build the jigs. I have subscribed.

@jaimecarbone6580 9 лет назад

Better than great!, you do have the skills to transmit your knowledge, that's so dificult for so many teachers, thank you!

@tronics666 9 лет назад

Thank you for the excellent lecture. You have a talent for explaining circuity.

@falconhawker 2 года назад

Intersting; Finally understand what a PIN diode is used for !

@pcfreak1992 Год назад

I don't know how you do it, but you put so much useful information in such a short and understandable video. Thank you!

@rjordans 6 лет назад

Just the explanation I was looking for. To bad you didn't include the attenuator construction itself yet but I guess that's something I should be able to figure out myself!

@joebell3567 4 года назад

Would have been interesting to apply a square wave to the control line of the pin diode to display pulsed transmission of a sinewave. Great range of video's well done. Joe G4PMY

@DavePKW 6 лет назад

I really enjoy your presentations on RF applications. Fantastic explanation. I love watching your practical experiments. Thank you.

@ltlt6117 9 месяцев назад

Thanks w2aew any time to want to learn something I will choose you're videos....

@girishk7003 4 года назад

Simple and practical explanation, hard to find in literature. Thanks a lot Alan !

@rockradio928 9 лет назад

You have helped fill so many gaps in my knowledge from things I never learn't properly at college. The five year one day a week City and guilds course my company sent me on was still teaching valve theory alongside transistors in the late 70's. As a home project, I once built the 1/4 wave line PIN switch into a 2 meter transceiver, to switch between transmit and receive without an aerial change-over relay, but never understood how it worked until now. From memory mine consisted of at least two 1/4 wave lines and at least four PIN diodes, but memory is a bit hazy now. Thank you for these wonderfully explained videos. For me the electronics hobby had died about 15 years ago when computers started to do everything far better than things I could build and hence little point building things any more, but your videos have reignited my interest. Thanks again. Howard UK

@gustavowkaiser 2 года назад

Best tutorial on pin diodes ever! Thanks a lot! 🙂🙋‍♂️🇧🇷

@chrisengland5523 2 года назад

All very clever. This is a completely different area of electronics to that which I'm familiar with. And so well taught too.

@anandawijesinghe6298 2 года назад

Wow! Great crystal clear instruction ! Thanks!

@ehsanollahshourezari2708 6 месяцев назад

Very good practical tutorial. thank you

@shanehogarth6373 Год назад

Great explanation, thanks

@daviddelman5105 2 года назад

Very informative video. I used this technique in my patented TV Pedaler® product but I never fully understood how it worked until I saw your "bucket of charge" explanation. Thank you!

@YellowsourceOrg 11 лет назад

Thanks you so much for all this very high quality content, you are the one with a clear signal and low noise. Thanks again.

@oh_wall Год назад

Such a helpful video, thank you for explaining the quarter wavelength property. Little tidbits of knowledge like that help a lot in understanding the full circuit

@mofaelectronics1295 2 года назад

great video thank you👍

@jonathanbignall1198 7 лет назад

Very interesting, I was reading recently about how different I.F filters were switched using diodes in H.F receivers and I was puzzled about how that worked; am I right in supposing they employ a similar principle to what you describe here? Thanks for the informative videos!

@tze-ven 4 года назад

You are truly awesome educator! Thanks for this great video! I wish you can do a video on antenna switching for direction finding; a feature available in BLE 5.1

@bhavani1089shankar 6 лет назад

Hi W2AEW , I request you to make a video on RF Tuners which are used to characterize High Frequency & High Power RF Transistors(GaN) , what I meant is load pull analysis(you have already done amazing tutorials on smith charts) , by the way you are one of the best instructors I have ever met in my life and actually what I observed in you is that the thought what comes in your mind , and what you talk or explain and later what you do on the bench are in unison and here in our culture in india we call that as TRIKARANA SUDHHI which is a rare quality , kudos W2AEW , it is always fun to watch your videos which edify Regards Bhavani Sankar Appalla

@w2aew 6 лет назад

I can add "load pull" to my very long list of future topics. Thank you for your very nice comments!

@jimbrown1559 2 года назад

As a former teacher, I recognize your excellence! Thanks.

@uiticus 2 года назад

This is so interesting. At that particular RF frequency the transmission line of the scope is 1/4 wavelength. And at that wavelength the opposite ends of the transmission line have opposite impedance! Is this only true with 1/4 wavelength or also true with multiples of 1/4 wavelength or even at any other wavelength?

@w2aew 2 года назад

The impedance inversion (around the system impedance) occurs at frequencies where the length is an odd multiple of quarter wavelengths long (1/4, 3/4, etc.). At the even quarter wavelength (1/2, 1, etc.), the impedance seen at the input of the line equals the impedance seen at the far end.

@uiticus 2 года назад

@@w2aew That is great! Thank you!