Those are "low frequency" diodes, good for a hundred MHZ or so, with limited output to maybe a GHZ. The really fast SRD's are good for outputs up into the tens of GHZ! You can find them on ebay from Russia, at reasonable prices. Note that these are usually used to multiply frequencies: lower frequency in: higher frequency out. So your input (drive) circuit should be tuned to your input frequency and your output should be tuned to your output frequency, which is usually a harmonic of the input frequency. They can be used to generate the local oscillator frequency of a microwave receiver.
After spending years collecting circuit boards, salvaging components, sorting and displaying them in custom shadowbox/frames, and studying all the weird variations… (particularly Vintage semiconductors)I’m always impressed by the insane variation and differences found in diode’s. I’ve got a shadowbox in my collection dedicated to strange diode’s. All “standard“ axial lead diode’s… Some of them are in there just because they look really weird or have super fancy paint jobs/color schemes… But most of them are just really weird and strange diodes meant for specific purposes. And I still find new ones and add them to the display pretty regularly. It’s super interesting.
This kind of diode is also used in sampling scopes to produce short sampling pulses out of not so short trigger pulses with which they are driven. I had the chance to tear down an old broken sampling scope in the early 80s when I wanted to build some type of sampling device. One way to look at the function of the diode is to regard it as a pin diode that has a low resistance when conducting as well as a capacity diode with a capacity that decreases with rising blocking voltage. At the beginning the Diode is conducting and has a charge. The trigger pulse which is coupled to the diode takes out the charge and makes it blocking. The impulse starts rather slowly in (100s of ps) and rises the depleting current via the inductivity of its path. During this first phase the diode is still conducting and the voltage does not change. When the charge is taken out the current is already at its maximum and with a rising blocking voltage at the diode the capacity drops so that the voltage rises even more steeply. In that way one could decrease the risetime of a 800ps ramp to below 100ps (or better with more skills). Just a description for an easy picture of what is going on.
Nice video thank you for posting it. I am surprised to see how well it worked at such low sine wave amplitude for the 25MHZ input. There are several application notes from HP where these diodes are discussed. One very interesting circuit is the one that drives the SRD forward via an inductor, and then a relatively wide pulse is applied such that it reverse biases the SRD. When all the carriers are depleted from the junction, the diode snaps off and then the energy stored in the inductor comes out as a very intense pulse which could be as short as 150ps. If you play around with these diodes, please post more videos about this.
Dear Top Dogs, IMSAI, GLASS, and W2AEW. I would love to see someone balance this pencil on a broom while on horse back. W2 intro was as PIN diode #118. The neg resistance and crazy osc window was very interesting. I watch your stuff 3 or more times, I love it, Thank You. Also Glass gave us a useful E-Circuit breaker and I found X-RAY Tony as added bonus. Mr IMSAI would you consider a short class on scope probing 120v audio equipment. I have always been a low voltage person. Is isolation transformer the only way. The moment Dave put up the don't blow scope warning ,guess what I want to do?
Thank You again for well ,everything. I should mention my real problem with main 120volt is putting seemingly good solenoid with storage caps on good transformer. I think inrush keeps blowing fuse. Do you think I should dump energy w power resistor and call it good? Slow down the cap charging, I think. Thank You from Bill Fischer
there are devices that are perfect for that. I forget the name though. they are resistive at the start and the resistance goes down after a bit. there are used in switching power supplies.
Those are "low frequency" diodes, good for a hundred MHZ or so, with limited output to maybe a GHZ. The really fast SRD's are good for outputs up into the tens of GHZ! You can find them on ebay from Russia, at reasonable prices. Note that these are usually used to multiply frequencies: lower frequency in: higher frequency out. So your input (drive) circuit should be tuned to your input frequency and your output should be tuned to your output frequency, which is usually a harmonic of the input frequency. They can be used to generate the local oscillator frequency of a microwave receiver.
Thanks glassy!
HP made ceramic packaged ones which were space qualified and worked up to 350GHz.
@@douro20 I'm stumped as to how I would measure the output at that frequency! :)
After spending years collecting circuit boards, salvaging components, sorting and displaying them in custom shadowbox/frames, and studying all the weird variations… (particularly Vintage semiconductors)I’m always impressed by the insane variation and differences found in diode’s. I’ve got a shadowbox in my collection dedicated to strange diode’s. All “standard“ axial lead diode’s…
Some of them are in there just because they look really weird or have super fancy paint jobs/color schemes… But most of them are just really weird and strange diodes meant for specific purposes. And I still find new ones and add them to the display pretty regularly. It’s super interesting.
This kind of diode is also used in sampling scopes to produce short sampling pulses out of not so short trigger pulses with which they are driven. I had the chance to tear down an old broken sampling scope in the early 80s when I wanted to build some type of sampling device.
One way to look at the function of the diode is to regard it as a pin diode that has a low resistance when conducting as well as a capacity diode with a capacity that decreases with rising blocking voltage.
At the beginning the Diode is conducting and has a charge. The trigger pulse which is coupled to the diode takes out the charge and makes it blocking. The impulse starts rather slowly in (100s of ps) and rises the depleting current via the inductivity of its path. During this first phase the diode is still conducting and the voltage does not change. When the charge is taken out the current is already at its maximum and with a rising blocking voltage at the diode the capacity drops so that the voltage rises even more steeply.
In that way one could decrease the risetime of a 800ps ramp to below 100ps (or better with more skills). Just a description for an easy picture of what is going on.
Nice video thank you for posting it. I am surprised to see how well it worked at such low sine wave amplitude for the 25MHZ input. There are several application notes from HP where these diodes are discussed. One very interesting circuit is the one that drives the SRD forward via an inductor, and then a relatively wide pulse is applied such that it reverse biases the SRD. When all the carriers are depleted from the junction, the diode snaps off and then the energy stored in the inductor comes out as a very intense pulse which could be as short as 150ps. If you play around with these diodes, please post more videos about this.
Dear Top Dogs, IMSAI, GLASS, and W2AEW. I would love to see someone balance this pencil on a broom while on horse back. W2 intro was as PIN diode #118. The neg resistance and crazy osc window was very interesting. I watch your stuff 3 or more times, I love it, Thank You. Also Glass gave us a useful E-Circuit breaker and I found X-RAY Tony as added bonus. Mr IMSAI would you consider a short class on scope probing 120v audio equipment. I have always been a low voltage person. Is isolation transformer the only way. The moment Dave put up the don't blow scope warning ,guess what I want to do?
simple way is to use a battery powered scope. th-cam.com/video/EUr3k9Jdx58/w-d-xo.html
measurement: th-cam.com/video/7rVoRypx9JI/w-d-xo.html
Thank You again for well ,everything. I should mention my real problem with main 120volt is putting seemingly good solenoid with storage caps on good transformer. I think inrush keeps blowing fuse. Do you think I should dump energy w power resistor and call it good? Slow down the cap charging, I think. Thank You from Bill Fischer
there are devices that are perfect for that. I forget the name though. they are resistive at the start and the resistance goes down after a bit. there are used in switching power supplies.
www.ametherm.com/inrush-current/ptc-thermistors-for-inrush-current-limiting
Thanks for the video. What are the applications of step recovery diodes and this particular circuit?
this circuit, pulse shaping, fast edge. they are used in oscillators, comb generators, oscilloscope trigger circuits