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Conspicuously absent are some of the analog circuit applications. Here are three of my favorites: 1. Frequency mixer, used for heterodyning, important in radio

• hshdhdhehd 11mo ago
  From my hobbying decades ago there is also the boring old rectifier to convert AC to a wavy DC.
  • deleted 11mo ago
    [deleted]
  • kennywinker 11mo ago
    Those are covered in the article
• nomel 11mo ago
  4. Varactors! https://en.wikipedia.org/wiki/Varicap https://en.wikipedia.org/wiki/Varicap Reverse biasing a diode at different levels changes the junction capacitance. Also used in radio, for things like variable filters. edit: oh, it's topped pinned comment!
• bob1029 11mo ago
  Zener diodes can be used as the basis for a quantum random number generator. https://opg.optica.org/optcon/fulltext.cfm?uri=optcon-1-7-1572 https://opg.optica.org/optcon/fulltext.cfm?uri=optcon-1-7-15...
  • phkahler 11mo ago
    These are also good noise sources and were use in several early video arcade games for producing explosion and spaceship thrust sounds. https://en.wikipedia.org/wiki/Noise_generator https://en.wikipedia.org/wiki/Noise_generator
• beckler 11mo ago
  Kinda interesting to hear about. I have a 500 chassis I’m slowly working on filling. I’m between the RND 535 or 543, and had never heard of a diode bridge comp before looking at the 535. What kind of 33609 clone do you have?
  • dietrichepp 11mo ago
    I have the Heritage HA-609A. I considered going 500-series. Maybe some day in the future. For now, I have two preamps and the HA-609A in a 4U rack, and most of my other gear is in storage. Keeping things light.
• RossBencina 11mo ago
  4. Voltage controlled filter, (diode ladder VCF), as used in the Roland TB303
  • ErroneousBosh 11mo ago
    Diode ladder, but also in various Sallen-Key designs like the Steiner-Parker Synthacon which we all now know from the Arturia Minibrute (Yves Usson probably made more of these filters than Nyle Steiner ever did!) and as I've mentioned elsewhere the Korg MS50. I think the Yamaha GX1 filters used a diode bridge too, probably using discrete transistors similar to the Korg 700S filter.
• cozzyd 11mo ago
  And a square law detector!
• gblargg 11mo ago
  Temperature sensor.
  • liffiton 11mo ago
    I did this once with a diode when I was a baby electrical engineer in college. But of course you need some kind of measurement circuit. So somehow(???) I figured out I could wire a diode into one axis of my analog Gravis joystick--hooked up to my soundcard--and get a fairly accurate and stable measurement of temperature by poking the monostable multivibrator (pretty sure that's what it was called) in the soundcard that would trigger the time it took to drain a set amount of charge through the joystick's x-axis/now-diode. Novices who don't have a clue nor know any better come up with the weirdest solutions. I have no clue whatsoever now what inspired me to even try something like that.
    • ErroneousBosh 11mo ago
      > I have no clue whatsoever now what inspired me to even try something like that. A combination of "what's the simplest thing that could possibly work?" and "well they didn't say you couldn't..."
    • HeyLaughingBoy 11mo ago
      And you managed to reinvent the single-slope ADC :-) https://www.cedarlakeinstruments.com/archives/841 https://www.cedarlakeinstruments.com/archives/841 https://www.monolithicpower.com/en/learning/mpscholar/analog-to-digital-converters/detailed-analysis-of-adc-architectures/integrating-adcs https://www.monolithicpower.com/en/learning/mpscholar/analog...
• summa_tech 11mo ago
  You could also make a high speed signal sampler. https://w140.com/tekwiki/wiki/Sampler https://w140.com/tekwiki/wiki/Sampler
• temporallobe 11mo ago
  Clipping diodes are common in distortion effects as well, especially guitar distortion pedals. Examples include silicon, germanium, LEDs, etc.
  • fuzzfactor 11mo ago
    I was always partial to the 6AL5 dual diode, which can handle over 300 volts: https://www.radiomuseum.org/tubes/tube_6al5.html https://www.radiomuseum.org/tubes/tube_6al5.html https://www.r-type.org/pdfs/6al5.pdf https://www.r-type.org/pdfs/6al5.pdf
• normel6 11mo ago
  PIN diode, a diode used as an AC on/off switch by passing current through it, very useful in RF circuits above 1GHz
  • analog31 11mo ago
    I'm always amazed at the circuit hacks that look utterly disgusting until you realize that they're the most practical solution at high frequencies.
• joconne 11mo ago
  Diodes are also used as a radiation detector in radiotherapy: https://oncologymedicalphysics.com/diode-detectors/ https://oncologymedicalphysics.com/diode-detectors/
  • 4gotunameagain 11mo ago
    And particle accelerators ! They mostly detect gamma radiation, and they are used in conjunction with other detectors (ram chips, mosfets)
• f1shy 11mo ago
  With some capacitors you can build a voltage multiplicator https://en.wikipedia.org/wiki/Voltage_multiplier https://en.wikipedia.org/wiki/Voltage_multiplier
  • saltcured 11mo ago
    Yeah, I remember one of these my brother cooked up to power a He-Ne laser tube way back when... It was lots of fun to apply to other off-label experiments too.
• timonoko 11mo ago
  Stereo decoder. You feed L+R and L-R to the corners of Full Bridge Rectifier and out comes Left and Right.
  • goodpoint 11mo ago
    I heard his voice while reading this.
• exDM69 11mo ago
  Two more from the world of analog music/guitar electronics: 1) Ring modulator: https://en.wikipedia.org/wiki/Ring_modulation https://en.wikipedia.org/wiki/Ring_modulation A device used to multiply two analog signals in time domain. Best known for the sound of the Daleks in the original 1960s Doctor Who series. Has some applications outside of music and sound effects. If you can find those old fashioned audio transformers, this effect does not require a power source. 2) Diode clipper: https://en.wikipedia.org/wiki/Clipper_(electronics) https://en.wikipedia.org/wiki/Clipper_(electronics) Two diodes in parallel with opposite polarities. Clips the incoming AC signal to a +/- diode threshold voltage. Put a high voltage gain amplifier stage in front of it and you get the classic electric guitar distortion tone you know and love. Allegedly works best with germanium-unobtainium diodes. In their absence, using two different kinds of diodes can also have pleasant tonal qualities.
  • ErroneousBosh 11mo ago
    > 2) Diode clipper: https://en.wikipedia.org/wiki/Clipper_(electronics) https://en.wikipedia.org/wiki/Clipper_(electronics) I don't even know how many Boss DS-1 clones I've made, but the first one was probably when I was in high school about 35 years ago.
  • actsasbuffoon 11mo ago
    So many distortion pedals use an op amp to run a signal into antiparallel diodes to create distortion. I’ve spent a few weeks trying to emulate it, and it’s a lot of fun. Different flavors of diode make significant changes to the way it sounds. Even things like LEDs can be used (they are Light Emitting Diodes, after all). Andy Simper of Cytomic is some kind of mad genius at this stuff. He’s created a painstakingly accurate emulation of the Ibanez Tube Screamer that allows you to change the values of basically every component in the circuit diagram. It’s jaw dropping: https://cytomic.com/product/scream/ https://cytomic.com/product/scream/ He’s also shared a ton of incredible information about how he emulates circuits. The math can get really intense. If anyone is looking for a fun project, I strongly suggest experimenting with circuit modeling. It’s a great workout for the brain.
    • 11mo ago
• adrian_b 11mo ago
  For log converters you should not use diodes, because their parasitic currents mask the current component that has an exponential dependence from the voltage. For log converters, bipolar transistors are used, because their collector current depends only on the ideal diode current of the base-emitter diode, not also on its parasitic currents, so the base-emitter voltage has a logarithmic dependence on the collector current, for a relatively wide range of currents.
• ErroneousBosh 11mo ago
  > 3. Diode ring, which provides variable gain, used in analog compressors like the Neve 33609 (I have a clone of the 33609, and I’m very fond of it) I just had a quick look at the service manual, but isn't that more of a diode bridge than diode ring? A Ring Modulator has the diodes connected nose-to-tail in a ring, but the gain cell in the 33609 looks more like a rectifier :-) You can see the same circuit in the VCF and (incorrectly drawn) in the VCA of the Korg MS50 synthesizer. In the former it acts as the "variable resistor" in a fairly straightforward Sallen-Key lowpass filter (there are two feedback capacitors, one to either side of the bridge, to attempt to prevent the input voltage also tuning the filter). On the VCA the diodes are drawn wrong but the pin numbers are correct.
• stevefolta 11mo ago
  In synthesizers, diodes are used in oscillators to shape triangle waves into sine waves.
• namibj 11mo ago
  Step recovery diode! Abuse minority carrier lifetime to very suddenly turn from resistive to capacitive just after switching from forward current to reverse bias; use the fact that the current wants to keep flowing to force it to concentrate into another step recovery diode that's about to cut out, in turn making the cut off spike even sharper, and on. Surprisingly capable for e.g. blasting a FET gate off while tanking the Miller effect gate current needs through sheer power of SRD-based-pulse-shaping. Because for e.g. GaN and SiC if you have to choose between ZVS and ZCS, you can take ZVS and just furnish a gate pulse that _makes_ the channel remain off as the current drops and the voltage soars. At least if you pull some tricks and make the current commutation loop sufficiently low inductance to keep your transistors from blowing out in self-inflicted overvoltage due to a current that needed to pass too high an inductance in too short a time. (Total drain charge is sadly fundamental to the channel's existence, and non-ZVS turn-on is unavoidably lossy. A majority carrier device is theoretically capable of just switching off though if you can arrange the structure for extremely low inductance.)