Spice simulation

Started by rickman in sci.electronics.design10 years ago 6 replies

I am using LTSpice III to simulate a filter using an LT1739 opamp. The filter is a two pole Multiple Feedback type set up for 4 kHz corner freq...

I am using LTSpice III to simulate a filter using an LT1739 opamp. The filter is a two pole Multiple Feedback type set up for 4 kHz corner freq and a gain of 10. When I run the simulation it oscillates (in spite of the fact that the opamp is supposed to be stable at gains of 10 or more, but I guess the gain is not 10 at the higher freqs). So I have added a resistor and capacitor across the +...


LM34 / capacitor / PIC ADC interaction? Aaaaarrrgh!

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

I'm running a couple of LM34 temp sensors into a PIC16F687. When running the ADC result is noisy. Here's what I've got: 1) On the LM34...

I'm running a couple of LM34 temp sensors into a PIC16F687. When running the ADC result is noisy. Here's what I've got: 1) On the LM34 temperature output pin is a sawtooth of about 200mVpp and 150uS period: |\|\|\|\|\ The 150us period seems unrelated to the ADC sampling rate - this which is sampled "on demand". 2) The ADC is set up for external reference (2.5V) which is clean and ...


Shaker LED flashlight

Started by amdx in sci.electronics.design10 years ago 18 replies

Just for fun and as a reinforcement of the electricity books my son has been reading. I bought a shaker flashlight. (magnetic flux cutting...

Just for fun and as a reinforcement of the electricity books my son has been reading. I bought a shaker flashlight. (magnetic flux cutting across wire moving electrons , the electrons then stored on plates of a capacitor) The flashlight has a magnet that slides back and forth through a coil. The flashlight cost $1.00. After I opened the package I noted a small screw rattling inside th...


Capacitor discharge question

Started by Mook Johnson in sci.electronics.design10 years ago 39 replies

Lets say there is a 60uF cap charged to 600V. The energy in that caps E = CV^2 which is ~ 22 joules If the cap has 3 ohms of ESR and the...

Lets say there is a 60uF cap charged to 600V. The energy in that caps E = CV^2 which is ~ 22 joules If the cap has 3 ohms of ESR and the output was shorted across a .1 ohm resistor. How much of the neergy would be dissipated in teh cap vs. in the resistor? Would it be as simple as 0.1/3.1 = ~ 3% of the total energyin the resistor? I cna get my hands on some resistors rated for 3-5...


Gate-drive for a large (325 A) thyristor.

Started by pete...@hotmail.com in sci.electronics.design10 years ago 6 replies

Hello everyone, I'm faced with an electronics problem. It's about a capacitor discharge spotwelder I'm building. For those who don't know what...

Hello everyone, I'm faced with an electronics problem. It's about a capacitor discharge spotwelder I'm building. For those who don't know what it is, these links explain best: http://www.philpem.me.uk/elec/welder/ http://www.philpem.me.uk/elec/welder/images/schematic.png http://sunstoneengineering.com/site/pages/products (these products make me drool) It basically discharges a large...


Capacitor Dissipation with Current Source

Started by D from BC in sci.electronics.design10 years ago 4 replies

I'm looking at datasheet http://www.panasonic.com/industrial/components/pdf/ABD0000CE45.pdf (MPP Film Cap) Datasheet: For 0.068uF to 4.7uF DF

I'm looking at datasheet http://www.panasonic.com/industrial/components/pdf/ABD0000CE45.pdf (MPP Film Cap) Datasheet: For 0.068uF to 4.7uF DF


TEA Laser Question

Started by amdx in sci.electronics.design10 years ago 4 replies

I have a question about the laser design on the url below. http://technology.niagarac.on.ca/staff/mcsele/lasers/LasersTEA.htm If you...

I have a question about the laser design on the url below. http://technology.niagarac.on.ca/staff/mcsele/lasers/LasersTEA.htm If you scroll down to the Prototype Design section and note the drawing. It shows a large plate capacitor with one bottom plate and a split (top) plate. In effect two plates. I'll describe the undrawn components: A hv dc power supply is connected across the sp...


OLED keyboard solution?

Started by Anonymous in sci.electronics.design10 years ago 1 reply

interesting idea:- OLED / LCD keyboard, but using optical fibre technology to send the signals and power to each key instead of wires. this...

interesting idea:- OLED / LCD keyboard, but using optical fibre technology to send the signals and power to each key instead of wires. this removes the need for any moving parts apart from the keys themselves. its possible to use infrared instead of visible light and individually address each OLED (continuous power to non active cells) with capacitor keep-alive on each key. perhaps...


Help my neighbour's kid with his school project...

Started by _ in sci.electronics.design10 years ago 30 replies

He's making a model of a tidal generation plant. The crucial bit for which he asked me for help is this: He's making a float that rises and...

He's making a model of a tidal generation plant. The crucial bit for which he asked me for help is this: He's making a float that rises and makes electricity with one of those tiny PM motors. He tells me he's getting about 300mV (cool; a 14-year-old not only knows what a DMM is but how to use it) and he'd like to run an LED. I though he might be able to charge a capacitor and dump it thr...


continuous mode,current mode control, boost circuit

Started by reggie in sci.electronics.design10 years ago 10 replies

Hi All, I am trying to understand the operation of a ML4824 Boost circuit operating in continuous mode using current mode control. I wanted...

Hi All, I am trying to understand the operation of a ML4824 Boost circuit operating in continuous mode using current mode control. I wanted to draw the critical voltage and current waveforms at each point through the circuit. Thus am trying to plot the ripple voltage across a boost capacitor with respect to the input full wave rectified 100Hz voltage in steady state conditions. How co...


Bootstrapping a MOSFET

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

Hello all! I've never had to post a question before, usually I'm able to search around and find something but this time I seem to be...

Hello all! I've never had to post a question before, usually I'm able to search around and find something but this time I seem to be stuck. I'm building a switching power supply (half bridge) and I'm trying to figure out a way to drive the High side MOSFET. I think I can use a bootstrap capacitor for it as the PWM will never be at 100%. What I need to know is the configuration of the compon...


Re: Capacitor Discharging with CMOS Gate

Started by Spehro Pefhany in sci.electronics.design10 years ago 12 replies

On Thu, 21 Feb 2008 19:37:31 -0800, the renowned John Larkin wrote: > On Thu, 21 Feb 2008 18:13:14 -0800, Joerg > wrote: > > > John...

On Thu, 21 Feb 2008 19:37:31 -0800, the renowned John Larkin wrote: > On Thu, 21 Feb 2008 18:13:14 -0800, Joerg > wrote: > > > John Larkin wrote: > > > On Thu, 21 Feb 2008 17:26:35 -0800, D from BC > > > wrote: > > > > > > > On Thu, 21 Feb 2008 16:53:39 -0800, John Larkin > > > >


Re: Capacitor Discharging with CMOS Gate

Started by John Larkin in sci.electronics.design10 years ago 6 replies

On Fri, 22 Feb 2008 09:54:26 -0800, Joerg wrote: > > > The thing is, we were driving down Valencia street and we > > ...

On Fri, 22 Feb 2008 09:54:26 -0800, Joerg wrote: > > > The thing is, we were driving down Valencia street and we > > *saw*a*parking*space*!! Of course, we nabbed it instantly, and then > > looked around to see what was nearby. It was Frjtz, a Belgian Fries > > place, with pretty good twice-cooked fries and some interesting beers > > on tap. > > > > A


Re: Capacitor Discharging with CMOS Gate

Started by Spehro Pefhany in sci.electronics.design10 years ago 1 reply

On Fri, 22 Feb 2008 11:18:37 -0800, John Larkin wrote: > On Fri, 22 Feb 2008 09:54:26 -0800, Joerg > wrote: > > > > > > > The...

On Fri, 22 Feb 2008 11:18:37 -0800, John Larkin wrote: > On Fri, 22 Feb 2008 09:54:26 -0800, Joerg > wrote: > > > > > > > The thing is, we were driving down Valencia street and we > > > *saw*a*parking*space*!! Of course, we nabbed it instantly, and then > > > looked around to see what was nearby. It was Frjtz, a


Re: Capacitor Discharging with CMOS Gate

Started by John Larkin in sci.electronics.design10 years ago 4 replies

On Sat, 23 Feb 2008 05:08:18 -0800 (PST), Winfield Hill wrote: > John Larkin wrote: > > Jim Thompson wrote: > > > John Larkin wrote: >...

On Sat, 23 Feb 2008 05:08:18 -0800 (PST), Winfield Hill wrote: > John Larkin wrote: > > Jim Thompson wrote: > > > John Larkin wrote: > > > > Jim Thompson wrote: > > > > > John Larkin wrote: > > > > > > Jim Thompson wrote: > > > > > > > Fred Bloggs wrote: > > > > > > > > Dave Platt wrote: > > > > > > > > > > > Huh? Latch up? > > > > > > > > > > The gate is shunting the charged cap to ground. > > > > > > > > > > (Chargin


Re: Capacitor Discharging with CMOS Gate

Started by Barry Lennox in sci.electronics.design10 years ago

On Mon, 25 Feb 2008 21:35:55 +0000, Baron wrote: > Joerg wrote: > > The only RS generator I have here is the old SMF RF generator. The >...

On Mon, 25 Feb 2008 21:35:55 +0000, Baron wrote: > Joerg wrote: > > The only RS generator I have here is the old SMF RF generator. The > > most spectrally quiet gen I ever had. But the steel tube in the > > oscillator has become tired after roughly half a century and it's > > pretty much unobtanium :-( > > Which tube is that ? Don't know about that on


Re: Capacitor Discharging with CMOS Gate

Started by John Larkin in sci.electronics.design10 years ago

On Mon, 25 Feb 2008 12:42:56 -0500, Fred Bloggs wrote: > > > Fred Bloggs wrote: > > > > > > Joerg wrote: > > > > > Fred...

On Mon, 25 Feb 2008 12:42:56 -0500, Fred Bloggs wrote: > > > Fred Bloggs wrote: > > > > > > Joerg wrote: > > > > > Fred Bloggs wrote: > > > > > > > > > > > > > > > John Larkin wrote: > > > > > On Mon, 25 Feb 2008 08:15:16 -0500, Fred Bloggs > > > > > wrote: > > > > > > > > > > > > > > > > > > > > > > John Larkin wrote: > > > > > > > > > > > > > On Sat, 23 Feb 2008 10:11:


Re: Capacitor Discharging with CMOS Gate

Started by Jim Thompson in sci.electronics.design10 years ago

On Tue, 26 Feb 2008 17:46:53 GMT, Joerg wrote: > John Larkin wrote: [snip] > > > Broadcom as usual patents any old crap. > > > >...

On Tue, 26 Feb 2008 17:46:53 GMT, Joerg wrote: > John Larkin wrote: [snip] > > > Broadcom as usual patents any old crap. > > > > IMHO the majority of new patents these days doesn't hold water anyhow. > > [...] I was the expert witness against Broadcom a few years ago... settled against Broadcom ;-) ...Ji


opamp as virtural ground

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

Hello. I'm building a virtual ground for a customer IC using an opamp (LT1802). The circuit that it interfaces to is an NMOS, whose...

Hello. I'm building a virtual ground for a customer IC using an opamp (LT1802). The circuit that it interfaces to is an NMOS, whose gate samples at 10MHz and outputs a current between 100uA and 200uA. The virtual ground connects to the drain of the NMOS. I'm also using a feedback resistor of 10KOhm to act as a I-to-V converter. My problem is.. I need a capacitor of about 10pF in parallel...


Ethernet interconnection between two embedded PC's inside one box

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

Hi, I have a question about interconnecting two embedded PC's by Ethernet. Our situation: - PC A has the LXT9785 Ethernet PHY of Intel,...

Hi, I have a question about interconnecting two embedded PC's by Ethernet. Our situation: - PC A has the LXT9785 Ethernet PHY of Intel, internal termination, with 1:1 transformer and 1nF/2kV capacitor at the TX and RX center taps at the secundairy side. - PC B has the 82562ET Ethernet PHY of Intel, termination near PHY, without 1:1 transformer. The specification of this ethernet PHY ...