## Charging a capacitor to 6kV

Started by in sci.electronics.design11 years ago 27 replies

I would like to charge a very small (1nF - 500pF) capacitor to fairly high voltage: 6kV (enough to get a reasonable spark). I believe...

I would like to charge a very small (1nF - 500pF) capacitor to fairly high voltage: 6kV (enough to get a reasonable spark). I believe the easiest way to do this is using a Flyback Transformer, or a Blocking Oscillator? I would like to use just two AA batteries for this. I don't especially want to wind my own flyback transformers - is it possible to use an ordinary audio transformer as a c...

## Flat Electrolytic Capacitors

Started by in sci.electronics.design11 years ago 14 replies

I stumbled across this... A 330uF 200V flatpack capacitor. http://www.cde.com/catalogs/MLS.pdf It's 1/2" thick. And also costs over \$100 ea...

I stumbled across this... A 330uF 200V flatpack capacitor. http://www.cde.com/catalogs/MLS.pdf It's 1/2" thick. And also costs over \$100 ea (mouser) Yikes! I need flatter... I'd like to know if I can get 150uF @200V crammed below 10mm without resorting to paralleling many capacitors. Can be axial, radial or SMD. Any mounting orientation is ok.. Currently Googling and browsing Digike...

## Simulation of a nonlinear capacitor

Started by in sci.electronics.design11 years ago 31 replies

Let's assume a nonlinear capacitor with c(v)=dq/dv. The q-v characteristic of the capacitor is given by the formula q=3*(v^3) Let's also...

Let's assume a nonlinear capacitor with c(v)=dq/dv. The q-v characteristic of the capacitor is given by the formula q=3*(v^3) Let's also assume that it's charged to 1V and then connected to a 0.2 Ohm linear ohmic resistance to discharge. I tried to write the equations for this simple circuit and then simulate the behaviour by approximating through the forward Euler method. My ...

## RMS approximation of Square/PWM signal

Started by in sci.electronics.design11 years ago 44 replies

Does anyone have a way to approximate and RMS voltage from a PWM signal. I want to regulate the RMS voltage sent to a lightbulb, but do not have...

Does anyone have a way to approximate and RMS voltage from a PWM signal. I want to regulate the RMS voltage sent to a lightbulb, but do not have the room for the inductor and capacitor required to carry 20+ amps of current. I need to feedback a voltage to the PWM controller that is proportional to the RMS voltage of the output. I don't need an EXACT RMS conversion, rather a ratio would be fin...

## Transistor Theremin by Alexander Zeyliger

Started by in sci.electronics.design11 years ago 3 replies

I would like to build the Transistor Theremin designed by Alexander Zeyliger but I need some help. I have some questions to be answered, I know...

I would like to build the Transistor Theremin designed by Alexander Zeyliger but I need some help. I have some questions to be answered, I know they are so basic.... What kind of capacitor is needed? I mean: ceramic, electrolytic, etc... It will works if the power supply is a 12VDC battery charger? It's so important to build it on a PCB? It's hard to build this project? I'll get any soun...

## MOSFET Drain-Source Leakage

Started by in sci.electronics.design11 years ago 9 replies

Hi : I have screwed up and designed a circuit neglecting the Vge=0 value of drain-source current in an (N-type) MOSFET (it is discharging an...

Hi : I have screwed up and designed a circuit neglecting the Vge=0 value of drain-source current in an (N-type) MOSFET (it is discharging an integrating capacitor and the 1 to 10uA makes a few % error which is too much) The only kludge I can do at this point is make Vge a few volts negative when I want the FET off, but I can't find any information on the effect of this on the leakage...

## LTSpice: How do make a Schmitt oscillator run?

Started by in sci.electronics.design11 years ago 8 replies

Ok, simple circuit: Schmitt inverter, 10K resistor from output to input, 1000pF capacitor from input to ground. Vh set to about 20% of Vhigh....

Ok, simple circuit: Schmitt inverter, 10K resistor from output to input, 1000pF capacitor from input to ground. Vh set to about 20% of Vhigh. Should happily oscillate but I get the error message "Time step too small". Also there is a noted dip in voltage down to about 80%, something which should even be possible with a digital behavioral device. What gives? How can I fix that and make i...

## Photodiode amplifier noise

Started by in sci.electronics.design10 years ago 33 replies

I'm embarrassed to ask this but - I have a high gain (transconductance) amp with a photodiode, biased to be a few hundred pF, on its input. I...

I'm embarrassed to ask this but - I have a high gain (transconductance) amp with a photodiode, biased to be a few hundred pF, on its input. I was tweaking it to optimise the noise levels and found the noise of the amp was way less than the noise of (the amp with the diode on the front). So I replaced the diode with a simple capacitor... and I still get extra noise when I fit it. It does...

## Driving BJT's

Started by in sci.electronics.design10 years ago 8 replies

The terminal voltages of a BJT are drastically different. Is there an issue when driving BJT's as with MOSFETS gate source voltage? I've done...

The terminal voltages of a BJT are drastically different. Is there an issue when driving BJT's as with MOSFETS gate source voltage? I've done some testing and it seems one doesn't have to worry too much about driving the base of a bjt because of the diode characteristics. One NPN I plan on using for a capacitor multiplier is rated at V_CB=1100V, V_CE=800V, V_BE=7V. Since this will be used i...

## Kanner Caps

Started by in sci.electronics.design10 years ago 7 replies

http://www.edn.com/archives/1996/060696/12df4.htm This seems to be the optimal way of reducing capacitor size in power supply filtering but...

http://www.edn.com/archives/1996/060696/12df4.htm This seems to be the optimal way of reducing capacitor size in power supply filtering but I'm unsure how to apply this to a high voltage system of several hundred volts. Right now I'm looking at using a capacitor multiplier circuit to achieve low ripple but the kanner cap seems better suited. I'm unsure of how to apply this to a high volt...

## Microphonic film capacitor

Started by in sci.electronics.design10 years ago 32 replies

I'm developing a frequency synthesizer. I was worried about ceramic capacitor microphonics, so I used these film capacitors in my loop...

I'm developing a frequency synthesizer. I was worried about ceramic capacitor microphonics, so I used these film capacitors in my loop filter: Panasonic ECPU1C105MA5 1uF, 16V, 1210, PPS (Farnell 969-4315) AVX CB017D0223JBA 22 NF, 50V, 1206, PEN (Farnell 165-7961) The 1uF is microphonic. Tapping it with a plastic rod produces FM on the VCO equivalent to ~ 20uV amplitude on the contr...

## Tube amplifier analysis

Started by in sci.electronics.design10 years ago 52 replies

http://www.schematicheaven.com/mesaboogie.htm I'm trying to understand the use of the amplifiers in some of the schematics...

http://www.schematicheaven.com/mesaboogie.htm I'm trying to understand the use of the amplifiers in some of the schematics above. http://www.schematicheaven.com/boogieamps/boogie_lonestar.pdf In several of the amplifiers there are preamp sections that do not use emitter degeneration but are configured as CC. V3B is one example. I'm a bit unsure why a capacitor was not added across the ...

## Breakdown voltage of PETG in Homemade Capacitor

Started by in sci.electronics.design10 years ago 3 replies

I'm working on building a high voltage capacitor. I have heard that PET has a very high voltage breakdown. I came across an excellent source of...

I'm working on building a high voltage capacitor. I have heard that PET has a very high voltage breakdown. I came across an excellent source of PETG (Polyethylene Terphthalate Glycol). How much will this affect the puncture resistance? I did a bench test that went alright for being in open air. I'm confident it will handle the voltage I need, but I'd still like some solid numbers. Couldn't fi...

## How to choose high speed transistors for FET gate driver?

Started by in sci.electronics.design10 years ago 5 replies

Hi - I'm trying to make a discrete gate driver for the synchronous N- MOSFET in a boost converter. The output of the boost converter is 43V max,...

Hi - I'm trying to make a discrete gate driver for the synchronous N- MOSFET in a boost converter. The output of the boost converter is 43V max, and I'll have another 10V or so sitting on top of that for the N- FET drive. That is being generated by the classic diode/capacitor bootstrap supply - so it's pretty weak and low power. What I'm confused about is how to select switching transistors f...

## Odd looking capacitor

Started by in sci.electronics.design10 years ago 32 replies

http://www.lazygranch.com/temp/funny_cap.jpg I camera-phoned this at Excess Solutions today. The text is something like Pflanzenal schulzart...

http://www.lazygranch.com/temp/funny_cap.jpg I camera-phoned this at Excess Solutions today. The text is something like Pflanzenal schulzart ohne kappe IP6s The cap has a cable attached to it with two wires. I was thinking motor starting cap, but I suspect not. Any ideas?

## ZVS converter - snubber helpful at turn-off?

Started by in sci.electronics.design10 years ago 2 replies

I am looking at doing a half-bridge LLC resonant converter design. Fairchild appnote AN-4151 Turn-on is not a problem as it is into zero...

I am looking at doing a half-bridge LLC resonant converter design. Fairchild appnote AN-4151 Turn-on is not a problem as it is into zero voltage as the lagging current commutates the current before the Fet turns on. I am wondering if placing a small capacitor (100pf-1000pf) across the Drain-Source might help to reduce transistor losses when turning off. It seems to me that at turn-off th...

## Capacitor Wizard (ESR Tester) Meter Movement

Started by in sci.electronics.design9 years ago 6 replies

I got this part: http://shop.midwestdevices.com/product.sc?productId=3&categoryId=1 when I really should have been looking for this complete...

I got this part: http://shop.midwestdevices.com/product.sc?productId=3&categoryId=1 when I really should have been looking for this complete assembly: http://midwestdevices.com/Brochure_Blowup.html The movement is a 1ma FS 50 ohm device. Can I build a complete do-it-yourself ESR tester from this meter movement? Thanks for reading!

## 433MHz transmitter ATA8402 Application note

Started by in sci.electronics.design9 years ago 10 replies

Has anyone here come across this application note for the ATA8402 (T5754) Atmel 433MHz...

Has anyone here come across this application note for the ATA8402 (T5754) Atmel 433MHz transmitter? http://www.atmel.com/dyn/resources/prod_documents/doc9115.pdf I have very little RF experience and I might be mistaken, but this AN is very dodgy indeed. I'm trying to make sense of the impedance-matching capacitor calculation. The main problem is that the equations are not accompanie...

## Driving capacitive loads with an H bridge

Started by in sci.electronics.design9 years ago 57 replies

Hi All, I need to drive capacitor with a triangle wave with no DC across the capacitor (i.e. a symmetrical bipolar drive but triangular) but...

Hi All, I need to drive capacitor with a triangle wave with no DC across the capacitor (i.e. a symmetrical bipolar drive but triangular) but it has to be efficient, i.e some kind of energy retrieval. Is it possible to use standard H bridge circuits to do this? Does anyone have any links or app notes? Thanks! Mark.

## Re: Magic capacitors!

Started by in sci.electronics.design9 years ago 1 reply

On Sun, 8 Aug 2010 20:14:28 -0700 (PDT), Bill Beaty wrote: > On Aug 7, 12:30?pm, Phil Hobbs > wrote: > > On 8/7/2010 11:17 AM, John...

On Sun, 8 Aug 2010 20:14:28 -0700 (PDT), Bill Beaty wrote: > On Aug 7, 12:30?pm, Phil Hobbs > wrote: > > On 8/7/2010 11:17 AM, John Larkin wrote: > > > > > Whatever term a physicist uses for "the differential charge on a > > > capacitor" or "the integral of all the current that has ever gone > > > through a capacitor" or "the charge on