What Oscillator is in This PS?

I had a '50 Nash which used the speaker field coil as the power supply choke... it'd run down the battery in one "night time in the park" session, so I'd always park pointed down-hill ;-)

...Jim Thompson

--
| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
 I love to cook with wine     Sometimes I even put it in the food

I have a nice Peavey stereo amp, 400 wats RMS per channel. Nice, but you can't lift it.

John

My dad had a Nash, a DeSoto, and a Kaiser. His purchase of a car was the kiss of death.

Then he bought a Chevy, apparently also a kiss of death, only a little slower. My mom's family were all Ford people.

John

How about the old capacitive voltage multipliers that required continuous manual operation of a multipole switch? Easier if the physical movement was eventually cammed to a rotary one.......

RL

That's tooobz isn't it? My 2x30W was "transistorized", and, IIRC, wasn't terribly heavy.

I did make a deal with the neighbor kid across the street... get "A" in Algebra, and I'd help him build a 400W guitar amplifier. That took two people to carry... I outfitted it with handles on each end to make it easier to carry. This was around 1972, so I had muffin fans on the heat sinks (arranged as a tunnel ;-) His father was so pleased that he built me a swimming pool for half-price.

Likewise helped another neighbor kid with his math... came home from work one day to find my yard fully equipped with a sprinkler system, for free ;-)

...Jim Thompson

--
| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
     It\'s what you learn, after you know it all, that counts.

When I was a kid my father had a Kaiser-Frazer station wagon... I think it was a 1956 model. I also had a '53 Packard... my father sold it while I was away at MIT, because my sister couldn't shift it :-(

So I bought a '61 Renault Dauphine for $1345 from Luby Chevrolet in Boston, then drove it cross-country to AZ (without any air- conditioning), kept it until 1968.

Had a '64 Dodge Dart, a '67 Cougar, a '68 Toyota Corolla, then a '77 Ford LTD, our last non-Japanese vehicle.

My father had Ford products after that, mostly Mercury, right up to his death.

Personally we've been Datsun/Nissan/Infiniti since 1977, though the #2 daughter went Lexus last year.

...Jim Thompson

--
| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
 I love to cook with wine     Sometimes I even put it in the food

No, it has a huge heat sink covered with 2N3772s or some such. The front panel alone must weigh 10 pounds... cast aluminum, black anodized, with raised, chromed letters. Lurid.

We drive a step-up transfomer to make 120-480 VAC at 50-400 Hz, and a step-down to get up to 200 amps, all for calibrating our AC power metering gadgets. I hacked an old board to make very stable, phase-adjustable sine waves (uP and dacs and ugly code), and the rest is 10-turn pots and such.

If they can be got to like math young, that's great.

John

I've never owned an American car. Austin-Healey, MG, Ford Fiesta (actually German), then two VWs. I keep a car for 12 years or so, or until it's totaled. I like German cars, although the Japanese, and lately the Americans too, are better quality.

I got my wife a Honda Fit, which is a very cool car. The Brat has a Jeep Rubicon, and we plan to attack this with it...

Google for images... some great stuff.

John

Some of the cheaper Russian night-vision scopes have a battery, a pushbutton, a transformer, rectifier+cap. When the image gets dim, pump the switch.

John

I built a number of tube amplifiers when I was a kid... easy when your dad owns a TV repair shop ;-)

But my first big amplifier was a 2x200W tube amplifier (done while I was a student at MIT and playing technician in Building 20 for Woodson/Melcher/Jackson) to drive a two-phase smear camera motor (for high-speed photos of MHD experiments). Even wound my own power supply and output transformers... big laminated C-cores held together with hose clamps ;-)

Yep, it's mostly about fear. Just broke #7 grandchild (a girl, 2nd grade) of her panic over math... I've got her doing page-after-page of addition/subtraction drill for accuracy (and speed, timed). Now she thinks it's fun ;-)

I'm also tutoring #3 granddaughter (HS sophomore) in Calculus... keeps me tuned up as well ;-)

...Jim Thompson

--
| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
 I love to cook with wine     Sometimes I even put it in the food

I'm typically at a 10-13 year car turnover rate. As soon as I see significant repair costs I dump 'em.

Yikes. I don't like heights or streets where you can't see the pavement in front of you, like most of the streets in SF ;-)

I was in such a situation once, on an Arizona hill that was all boulders, passenger in a friend's Jeep. I got out and walked beside the Jeep as he drove it down... nasty :-(

...Jim Thompson

--
| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
 I love to cook with wine     Sometimes I even put it in the food

Once Ikea tried to do a delivery here in the area. Got stuck, had to drive the truck back to the main road (in reverse!) and come back next day with a 4WD truck.

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.

cycle

caps

regulate

as

R1

I duplicated your trouble.

The problem is on the falling edge of the flyback pulse.

The timing cap just discharges enough so that the base drive to Q2 falls off, and then Q2 "lets go" at some high inductor current.

When the flyback pulse ends it swings back to

0V, which fires Q1 again through its input divider. Since the inductor current is very low at that point, the timing cap still has plenty charge to support driving Q2 for a runt pulse, or even a series of runt pulses depending on your choice of component values.

FIXES Using the oscillator to drive a separate switching transistor would avoid these kinds of feedbacks and interactions, but defeats the circuit's simplicity.

Or, choose the operating frequency such that the next pulse is *supposed* to coincide with the end of the previous pulse.

You could also just choose to ignore it. I only see it for a few cycles during ramp up, and it carries little or no performance penalty.

Best regards, James Arthur

gain

wrong,

Mine was a tube amp. A nice strong twang on the E-guitar and the

130V/16A breaker tripped. Poof. Dark.

Oh, regarding the output transformer, there wasn't any. Rewound the coil of a huge circus PA speaker. Afterwards I vowed never, ever to attempt that again. I think half of the cuss words I ever said were mumbled on that day.

[...]

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.

R1

cycle

voltage

caps

regulate

oscillator as

of R1

resistance

Play

Yes, exactly. I was also thinking increasing the values of the voltage dividers reduces the impact of the inductors pulses. Also the bias voltage on Q2 can be adjusted a bit to reduce Q2s sensitivity to variations induced in Q1 output.

I also have found enough data to model the coupling transformers. Regular voice/data transformers run about 170mH on the primary with a coupling coefficient of about 0.98. Ultrawideband Xformers run 500mH to 700mH on the primary with a coupling coefficient of about 0.991.

Your DCR figure of 40 ohms is a bit low, unless the primary can handle several watts of input. 400mW Xformers run about 60-70 ohms.

Fred

wondering

by R1

the cycle

voltage

the caps

regulate

oscillator as

of R1

resistance

Play

What is the purpose of that diode, D5. Somebody said it was to back bias the Xformer/choke. I noticed its necessary.

Good old vibrator power supplies. I saw an unusual one where the vibrator did synchronous rectification a well. It ran at 115 Hz. Haven't seen one since i was a teen though.

cycle

caps

regulate

as

IME for transistors 2:1 to 4:1 and 5:1 to 10:1 for tubes. But that was a long time ago and i could misrecall.

R1

cycle

voltage

caps

regulate

oscillator as

R1

resistance

Play

I found it quite intuitive. Think of Q1 operating as a switch. And the discharge current of C2 must go through the Q2 base resistor.