Hello. I have built a phase shifted converter based in the UCC28951 from TI, but I have problems with stability. The load has built-in...

Hello. I have built a phase shifted converter based in the UCC28951 from TI, but I have problems with stability. The load has built-in capacitors and the converter oscillates wildly. I have changed the Type-II compensator to a Type-III one, but oscillations do not stop. Calculation of the Type-III compensator is based in application note SLVA662 from TI. The input voltage is 48 V, ou...

I'm backing off of the neon sign transformer 12kV power supply. For the reasons I was told, the low frequency requires big capacitors. Also, I...

I'm backing off of the neon sign transformer 12kV power supply. For the reasons I was told, the low frequency requires big capacitors. Also, I ordered 20kV caps from Amazon and 6 of the 12 failed at under 4kV. I should have read the reviews, it is well shown these fail. So, I want a continuous DC voltage, I can imagine the old tripler design gave a decent continuous DC, but I'm look

The circuit has to operate in both differential input and single ended input modes. When in single ended input mode, there's no way to ground one...

The circuit has to operate in both differential input and single ended input modes. When in single ended input mode, there's no way to ground one input, so it will float. In this circuit, the two inputs are tied through C9. So I can't see how this circuit would allow single ended operation. If, however, C9 is split in two, as a pair of 1 uF capacitors to ground, that would se

I've read that the exponential behavior predicted in e.g. RC circuits by taking the Laplace-domain impedance of capacitors to be 1/sC leads to a...

I've read that the exponential behavior predicted in e.g. RC circuits by taking the Laplace-domain impedance of capacitors to be 1/sC leads to a causality violation, and that after much testing of many capacitors some guys named Westerlund and Eklam determined that the true behavior is a probably a power law, which I guess means the dv/dt in I = C dv/dt would actually have to be some kin...

Hi, all, We're making some 7-pole active lowpass filter boards, primarily to go into test systems (ours and other people's). It would be...

Hi, all, We're making some 7-pole active lowpass filter boards, primarily to go into test systems (ours and other people's). It would be convenient to be able to use 0.5% resistors and 5% capacitors. There are 2% caps available in most of the range we want, but they're expensive and relatively scarce. If we could get a few reels of 5% caps, we could dork the resistor values to get ...

The Spectrum has a recent article/book review: https://spectrum.ieee.org/open-circuits "The Inner Beauty of Electronic Components" The...

The Spectrum has a recent article/book review: https://spectrum.ieee.org/open-circuits "The Inner Beauty of Electronic Components" The article includes statements clearly addressing the electronic clueless. E.g., "Capacitors are fundamental electronic components that store energy in the form of static electricity." So who are the Spectrum's readers? I always thought it was EE's/des...

Family. Hiking. Cooking. Eating. I need an electronics break. I'm thinking about a product that measures large (as in 60 feet...

Family. Hiking. Cooking. Eating. I need an electronics break. I'm thinking about a product that measures large (as in 60 feet tall) capacitors, and it needs a tough, hard to damage TIA. AC coupling is fine, and the range is basically audio. Something like this: https://www.dropbox.com/s/mrf7kbvtboktstz/Tough_TIA.jpg?raw=1 One could close a fancy bias servo loop on Q1, but it's hardly...

I have an inductor wound on some 22mm plastic pipe, so essentially air-cored. It's over 120 turns, 700mm long and uses resistance wire. It's...

I have an inductor wound on some 22mm plastic pipe, so essentially air-cored. It's over 120 turns, 700mm long and uses resistance wire. It's about 12uH. There are 30 capacitors connected evenly along the coil commoned to a copper pipe busbar. It simulates a long, peculiar transmission line. I want to LTspice it. OK, lots of small inductors with some resistance and the capacitors. ...

Hi I am working on a design where we are monitoring a relay, if it has been energized. That is done with high ohmic resistor and a source...

Hi I am working on a design where we are monitoring a relay, if it has been energized. That is done with high ohmic resistor and a source voltage, detecting a current when drawn But, contact wetting could be a problem, so have added a small capacitor on the contacts, so when they are closed a relatively high current runs for a short period of time to punch through the oxide layer of ...

Hi, all, Some years back, in one of my more inspired moments, I bought a lifetime supply of 1.5 nF Soviet feedthrough capacitors from eBay. ...

Hi, all, Some years back, in one of my more inspired moments, I bought a lifetime supply of 1.5 nF Soviet feedthrough capacitors from eBay. I have about 1,500 of them left, which should be good for building protos till about 2175 AD. Feedthroughs are great because they let you get supply and control wiring in and out of RF shields without trashing the shield effectiveness. They s...

I have never known what the electrolyte is made from, inside of electrolytic capacitors. Is it a water based material, or oil based? If its...

I have never known what the electrolyte is made from, inside of electrolytic capacitors. Is it a water based material, or oil based? If its water based, it will likely freeze if left outdoors in cold weather. For example, your car radio has caps, and if it's parked outdoors in the winter, the caps in it will freeze. Yet, I have never found my car radio working poorly in cold weather. This ma...

LM317's like some ESR in their output capacitors. I don't want any electrolytic or tantalum caps in my new thing, just ceramics, and the sim...

LM317's like some ESR in their output capacitors. I don't want any electrolytic or tantalum caps in my new thing, just ceramics, and the sim sure rings: https://www.dropbox.com/s/11b3w42nsvpliki/317_nocomp.jpg?raw=1 But this fixes it: https://www.dropbox.com/s/9q80heyfbwh5frp/317_comp.jpg?raw=1 This ain't rocket science, but I haven't seen it done before. -- John Larkin ...

Speaking of high reliability... I think that it is often a somewhat neglected issue, so I start this thread as a mean to collect *practical*...

Speaking of high reliability... I think that it is often a somewhat neglected issue, so I start this thread as a mean to collect *practical* observations for people who care about long MTBF. In other words, "if I had to build a device which should last 50 years, I would... what?" Resistors (if not overloaded): immortal Ceramic capacitors: as above Tantalum/nobium caps: ? Electrolytic...

I have this circuit driving a pulsed laser. I want to compute the energy dumped into the laser and the energy stored in the power...

I have this circuit driving a pulsed laser. I want to compute the energy dumped into the laser and the energy stored in the power supply capacitors. The ballpark is 120 amps into a 20 volt laser for a few hundred microseconds. What I did was create a "B" behavioral current source whose equation is I = V(LASER) * I(LASER) which represents power, and dump that into a 1 farad cap. The...

For most of my projects I use either a 14.7456 MHz crystal (57600*256) = or=20 20.000 MHz (for USB 96 MHz 24*f/5). The 20 MHz crystal I am using...

For most of my projects I use either a 14.7456 MHz crystal (57600*256) = or=20 20.000 MHz (for USB 96 MHz 24*f/5). The 20 MHz crystal I am using = specifies=20 a 20 pF parallel load, but my boards have 12 pF capacitors. I just = noticed=20 this and I think the value had been selected for a previous brand of=20 crystal, but the oscillator frequencies measure pretty close to the = ideal=20 ...

Hi For an application I need to protect the electronics of an RS485 interface from surges (8/20us 1kV pulse) The normal way be to use a...

Hi For an application I need to protect the electronics of an RS485 interface from surges (8/20us 1kV pulse) The normal way be to use a transzorb, in a SMA housing or even a SOT23 device. That is not possible since we have to be able to withstand up to 30V DC on the bus also (that is handled by a special RS485 IC) The problem is that the selected breakdown voltage of the transzorb ...

I've just built up a batch of PCBs with several LM317 and LM337 regulators on them. As this thing will be in a hot environment, I wanted to...

I've just built up a batch of PCBs with several LM317 and LM337 regulators on them. As this thing will be in a hot environment, I wanted to avoid electrolytics so I used 10uF MLCC ceramic capacitors on the inputs and outputs of the regulators. Now that I have built it, all of the regulators oscillate! I had thought that it was only LDOs (with the drain or collector of the pass device ...

Folks, This afternoon I took the old HP-4191A apart. Yesterday in the middle of some measurements it went pop-pop-pop, loud, like...

Folks, This afternoon I took the old HP-4191A apart. Yesterday in the middle of some measurements it went pop-pop-pop, loud, like firecrackers. I ran over and turned it off, upon which the popping stopped. An immense amount of light-gray smoke wafted out and it had an odd stench to it. The stench lingered for hours. I can't find any source and upon powering it up the analyzer worked fin...

Hi all. I'm running through some test of a phototransistor signal conditioner, and I'm facing with wild noise issues. The conditioning is a...

Hi all. I'm running through some test of a phototransistor signal conditioner, and I'm facing with wild noise issues. The conditioning is a basic TIA stage: http://i.imgur.com/PcgglKZ.png Feedback resistor is 5K, feedback capacitor is 470pF, negative bias is -12V, and photocurrent is in the range 8uA-800uA. The bandwidth should be about 50kHz. Opamp is OPA2277UA. Problem is that phototrans...

Hey Been trying to find the post with the lossless snubber, with AFAIR a capacitor from the drain node to a regenerative point. I am working...

Hey Been trying to find the post with the lossless snubber, with AFAIR a capacitor from the drain node to a regenerative point. I am working on a 2 switch flyback and some other schemes, but would like to try that novel idea out.... Anyone knows a pointer to the thread? Regards Klaus