A nice component identifier machine

Started by bitrex in sci.electronics.design4 years ago 12 replies

ATMega328 8-bit uP driven, it does a lot of stuff! $15.50 with an enclosure on Amazon:

ATMega328 8-bit uP driven, it does a lot of stuff! $15.50 with an enclosure on Amazon:


Electrolytic capacitance degradation, linear?

Started by Klaus Kragelund in sci.electronics.design4 years ago 17 replies

Hi Normally the lifetime of an electrolytic capacitor is defined as the minus 20% capacitance point But it seems it continues to degrade...

Hi Normally the lifetime of an electrolytic capacitor is defined as the minus 20% capacitance point But it seems it continues to degrade linearly beyond the rated lifetime point https://goo.gl/images/K8rSM6 So, if a bigger capacitance is marginally higher cost, one could “use” the capacitance beyond the minus 20% point if the application works at that low


AC offline to low-V supply, with a cap

Started by Winfield Hill in sci.electronics.design4 years ago 77 replies

Years ago we had threads about the ugly but seemingly simple scheme to get 12V DC at 5mA, etc, with a film capacitor straight to the AC ...

Years ago we had threads about the ugly but seemingly simple scheme to get 12V DC at 5mA, etc, with a film capacitor straight to the AC line. We said, gotta have a series resistor to minimize the startup inrush current. Does anybody recall a specific instance of this scheme being used commercially? Paul and I are days away from turning in the manuscript on our new x-Chapters ...


Common collector amplifier and amplitude modulation

Started by Anonymous in sci.electronics.design3 years ago 20 replies

Could some electronics guru here shed some light on this Could a single stage common collector amplifier exhibit amplitude modulation ? I have...

Could some electronics guru here shed some light on this Could a single stage common collector amplifier exhibit amplitude modulation ? I have the SPICE model of a simple common collector amplifier consisting of two base bias resistors, a collector resistor and an input and a output DC blocking capacitor, as well as a source and a load resistor of 50.0 Ohm. The BJT collector is connected to ...


λ-Bridge Thermal Conductor

Started by Winfield Hill in sci.electronics.design3 years ago 26 replies

Sometimes you encounter things that blow your mind. New-product email from Mouser, with a section titled "RF Solutions from AVX", has a...

Sometimes you encounter things that blow your mind. New-product email from Mouser, with a section titled "RF Solutions from AVX", has a mind-boggling item, "AVX Lambda-Bridge Thermal Conductors". It's just an 0402, 0603 or 0805 package; could be a resistor, but it's an open circuit; could be a capacitor, but with no capacitance, well, less than 0.1pF anyway. https://www.mouser.co...


Voltage variable-capacitance capacitors

Started by Bill Beaty in sci.electronics.design3 years ago 29 replies

No need for VC tuning diodes, we have VC variable ceramic capacitors. Use any large-value ceramic capacitor. Measure the uF while applying a...

No need for VC tuning diodes, we have VC variable ceramic capacitors. Use any large-value ceramic capacitor. Measure the uF while applying a DC bias, and watch what happens. I tried this on a 22uF 10V cap, in 0805 package. At 2.6V, capacitance decreased from 21uF to 10uF! At the rated 10V, capacitance was 2.55uF. WTF The suppliers have apparently been concealing the fact that, ...


troubleshooting: Agilent 3616A power supply

Started by Cydrome Leader in sci.electronics.design3 years ago 3 replies

I'm only asking as maybe this is a common failure mode somebody has seen. Got an actual Agilent badged 3616A power supply, one of the half-rack...

I'm only asking as maybe this is a common failure mode somebody has seen. Got an actual Agilent badged 3616A power supply, one of the half-rack width deals with the LED voltage and current display and a single 36volt 1.6A output. Out of the blue, the current meter seems to read strange phantom currents that decrease slowly, like you're charging a large capacitor. It also seems to hav...


LM1117 with ceramic cap load

Started by John Larkin in sci.electronics.design3 years ago 7 replies

I did this with the LM317, so thought I'd verify it with the...

I did this with the LM317, so thought I'd verify it with the 1117. https://www.dropbox.com/s/cboxe03ef0dhy22/LM1117_Cload.JPG?raw=1 https://www.dropbox.com/s/yt4ehon0pzi8ni5/LM1117_Comp.JPG?raw=1 Adding that 47n cap makes it low-esr capacitor load stable. I have no clue why. I really like the LM1117. It's cheap, tough, and has lower dropout than the 317. We've used 56,000 so far....


SPICE simulations of non-ideal inductor behavior

Started by amal banerjee in sci.electronics.design3 years ago 2 replies

Could some electronics guru here plaease shed some light on this ? I am running SPICE simulations of non-ideal inductors, that include high...

Could some electronics guru here plaease shed some light on this ? I am running SPICE simulations of non-ideal inductors, that include high frequency effects as skin and proximity. I am trying to see the resonance peaks when the non-ideal inductor is placed in parallel with a fixed value capacitor. The AC sweep freqienncy is brtween 100 MHz 10 GHz. As I vary the fixed capacitor value, so...


High Q smd capacitors

Started by amdx in sci.electronics.design3 years ago 56 replies

Reading a forum, a member is comparing the Q of an smd capacitor to a good air capacitor. Maybe?, I don't have a reference of the Q of a good...

Reading a forum, a member is comparing the Q of an smd capacitor to a good air capacitor. Maybe?, I don't have a reference of the Q of a good High Q capacitor. Range 20pf to 400pf. For further reference is is used in a ring down Q meter. See last post on this page. > http://theradioboard.com/rb/viewtopic.php?f=2&t=8691 The page includes a sales sheet of a 1210 smd in Chinese.


Bitscope (Micro BS05) and 32bit Linux

Started by Johann Klammer in sci.electronics.design3 years ago 4 replies

I got one of those. Today, I tried to set up two oscilloscope probes. (the frequency compensation capacitor) I noticed the following...

I got one of those. Today, I tried to set up two oscilloscope probes. (the frequency compensation capacitor) I noticed the following things in bitscope-dso: when adjusting the cap, the waveshape doesn't change, but the amplitude does. at 250kHz it's almost triangles regardless of capacitor setting. 50kHz looks acceptable. I am also not sure what sort of filter it has and how to turn i...


Aluminum electrolytic capacitor failure modes and ripple current ratings

Started by Ethan Petersen in sci.electronics.design3 years ago 14 replies

I am trying to get a handle on ripple current ratings for capacitors, starting with the ChemiCon KZN series. The data sheet has specifications...

I am trying to get a handle on ripple current ratings for capacitors, starting with the ChemiCon KZN series. The data sheet has specifications for rated ripple current and maximum temperature. It seems I can reliably operate well beyond the ripple current rating, but I don't have a good understanding of what the real limitations are. How do capacitor manufacturers come up with the


capacitor placement

Started by rob d in sci.electronics.design3 years ago 5 replies

Hi all. I am routing GBit FPGA links at 12GBit and I am having an issue with DC blocking capacitor placement with Ultrascale plus devices. I am...

Hi all. I am routing GBit FPGA links at 12GBit and I am having an issue with DC blocking capacitor placement with Ultrascale plus devices. I am new to the company and I am up against "we always do it that way". The closest I can get some of the caps is 13mm from the BGA pad but that causes horrendous other routing issues. Assuming the link is a sine wave then the "edge" takes 83p


Film capacitor as power-supply filter

Started by Anonymous in sci.electronics.design3 years ago 200 replies

Is there any reason not to use a 20-uF 900-volt film capacitor as a power supply filter? I'm updating a vintage Heathkit capacitor checker that...

Is there any reason not to use a 20-uF 900-volt film capacitor as a power supply filter? I'm updating a vintage Heathkit capacitor checker that I use regularly for re-forming electrolytics, and its power supply filter is currently two 40-uF 450-V in series, without balancing resistors; applied voltage is nominally 600 V DC. This hasn't given any trouble, but I'm uneasy about its future. Now...


Things that go boom? Need to present to some kids

Started by Anonymous in sci.electronics.design3 years ago 36 replies

Hi Every year I teach a class in 7th grade about electronics and space stuff I normally end the presentation with a reverse power capacitor...

Hi Every year I teach a class in 7th grade about electronics and space stuff I normally end the presentation with a reverse power capacitor that goes boom, just so they at least get excited about that. But, any other component that makes a large boom? (I would like to avoid the cap, since it spills electrolytics and smells bad DPAK2 FET, with 30W disipated? Tantalum reverse biased? ...


Class E amplifier question

Started by amal banerjee in sci.electronics.design3 years ago 5 replies

Here is a question for all electronics gurus here. Can a class E amplifier be termed efficient - given the shunt capacitor from BJT collector...

Here is a question for all electronics gurus here. Can a class E amplifier be termed efficient - given the shunt capacitor from BJT collector to ground, which is an AC short -- unless the capacior value is very small, such that the capacitive reactance is large. Any flaws in this argument ?


C0G AC derating

Started by Piotr Wyderski in sci.electronics.design3 years ago 4 replies

Hi, Polypropylene capacitors are no longer the only choice in the ~20nF/1kV+ range. Now there are C0G MLCCs as well. It makes me think...

Hi, Polypropylene capacitors are no longer the only choice in the ~20nF/1kV+ range. Now there are C0G MLCCs as well. It makes me think whether they would work reliably as the LLC resonant capcitors, in split capacitor resonant half-bridge topology preferably. The polypropylene high frequency derating curves are available, but I see no similar specification for the ceramics. So is th...


Weird LLC current limiter

Started by Piotr Wyderski in sci.electronics.design3 years ago 3 replies

I have just found this pretty bizarre idea: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.665.5375&rep=rep1&type=pdf It uses a...

I have just found this pretty bizarre idea: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.665.5375&rep=rep1&type=pdf It uses a transformer to limit the voltage swing at the resonant capacitor. Great, but why wouldn't they use a bidirectional TVS for the same purpose? That wouldn't result in a paper, eh, would it? Best regards, Piotr


Schottky diodes for RF application

Started by amal banerjee in sci.electronics.design3 years ago 3 replies

Could someone here shed some light on this ? I am experimenting with envelope detection at RF frequencies with SPICE. The mixer is a simple...

Could someone here shed some light on this ? I am experimenting with envelope detection at RF frequencies with SPICE. The mixer is a simple SPICE B signal source as B0 3 4 V(1)*V(2) where 1, 2 are the nodes at which the two signal sources are attached. THe mixer output is fed into a Schottky diode(1N5818, BAR42 etc.,) and a shunt capacitor is attached to the Schottky diode cathode. ...


high voltage charge pump

Started by Hul Tytus in sci.electronics.design3 years ago 89 replies

Anyone familiar with a high voltage charge pump designed as a step down power supply? The voltage is between 175 & 200. Numerous high...

Anyone familiar with a high voltage charge pump designed as a step down power supply? The voltage is between 175 & 200. Numerous high voltage versions exist using inductors, (Onsemi has one that is "self supplied" which is attractive) but not a one that works with just a capacitor. Are there any out there I've missed? Hul