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May
14
comment Can an electric circuit do recursion?
@supercat AFAIK, a vacuum-isolated circuit (or even an air-isolated one) could have precise capacitors, and balancing them to 1ppm using an impedance bridge is not extraordinarily hard. You could probably do it just fine in the 60s at the latest. As for the switch, you don't need a capacitance-free device, just a constant-capacitance device. I think that a 16-bit DAC could be demonstrated that way, using air capacitors and a mechanically-actuated switch. With a few tiny dielectric spacers, made of a good material, between the large plates, their dielectric absorption could be kept at bay.
May
13
revised What is MECL 10h or 100 K ECL logic levels and how do I use them?
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May
13
revised What is MECL 10h or 100 K ECL logic levels and how do I use them?
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May
12
revised What is MECL 10h or 100 K ECL logic levels and how do I use them?
added 568 characters in body
May
12
answered What is MECL 10h or 100 K ECL logic levels and how do I use them?
Jan
12
awarded  Revival
2018
Jul
12
awarded  Yearling
Jun
27
comment Use of malloc in PIC
@supercat You're right. I was overzealously dramatic indeed. There are formal proofs of those guarantees.
2017
Dec
29
comment Type “X2” line filtering capacitor failing as short circuit
I think that all of a particular vintage of those old RIFAs will fail just like that. They are essentially a "replace on sight" sort of a part, when sufficiently old. Any of those made in the 80s or earlier certainly should be replaced without question.
Dec
21
comment How to protect microcontroller board 1-wire from accidental +12V connection?
Pretending that a power supply bus in a modern microcontroller board is an ideal voltage source is disingenuous and a way to let the magic smoke out. It's not a guideline anyone should follow.
Dec
21
comment How to protect microcontroller board 1-wire from accidental +12V connection?
The input voltage source will have much faster rise times - an "accidental short" doesn't take 100us, and any sort of a spice model should include the parasitic inductances to give you an idea of how high of an overvoltage will result from those inductances' ringing. All in all, the circuit presented is a textbook example - of how not to approach such problems. It has place in a physics textbook perhaps, where spherical cows are a necessary simplification, but not in an electronics textbook :)
Dec
21
comment How to protect microcontroller board 1-wire from accidental +12V connection?
Given the low power nature of many a microcontroller circuit, dumping 60mA from a 12V power source into a 5V rail has a high chance of destroying your circuit. This is bad advice. D1 should be a modern SMT bidirectional clamp, and then there's no need for D2 either. Such clamps will turn on much faster than a 1N5817 would. In fact, suggesting a rectifier that is doesn't have switching times specified in the datasheet is a bad idea as well.
Aug
25
awarded  Necromancer
Aug
15
revised Why is USB cable maximum length is shorter than in RS232?
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Jul
12
awarded  Yearling
May
19
comment Why does my electret microphone amplifying and filtering circuit output so much noise?
Re 1: Never mind that the 5k equivalent resistance of the source itself is noisy! Re 3: The op-amp feedback loops don't properly limit the bandwidth either. There needs to be a capacitor across every negative feedback resistor!
2016
Dec
5
answered Why is sine wave preferred over other waveforms?
Dec
5
answered Analog isolation vs Digital Isolation
Dec
5
comment 74HC595 overheating problem when controlling NPN transistors
Your schematic lies to you: whatever layout/breadboard you're using introduces parasitic elements that you don't see on the schematic, and thus ignore. Most likely all the long wires/traces in your system, coupled with fast rise/fall times of the logic signals, generate decent ringing that destroys your logic. This question cannot be answered until you include readable pictures of the layout and/or breadboard used. Once you do, try and model the parasitics and figure out whether they play a role. My gut feel is that they do.
Nov
8
awarded  Civic Duty