rectifier waveform

The peaks thing bothered me when I was building my clock so instead, I went for detecting zero crossings this way.( My first attempt with Andy's. Hope it makes sense.)

1N914 ____ | | +-+---------o->|--o--|7805|--o--o------o------. A A | | |____| | | | | -+ | | | | | | | | -(-+ .-. | | | | .-. | A A | | | | | - | | | +-+-. 1K | | | | | ^ 1K | | | | '-' | | | | '-' | | | | | | | | |\\| AD790 | | | | | | o----|-\\ | | | | | | | | >- | o-----)----)-----)--o------)----|+/ 120 Hz pulse | | | | | | | |/| | | | | | | | | to IRQ | | | | | | ' | | .-. | | | | .-. | | 1K | | | | | - 1K | | | | | | --- | --- ^ | | | | '-' --- | --- | '-' | | | | | | | | | '-------o-----o----o-----o--o------o------'- 1N914 (created by AACircuit v1.28.6 beta 04/19/05

GG

AD790 ! Are you made of money ?

Graham

I used them in a real expensive project that actually needed the performance and I had a couple left over. I'm sure an LM311 would do though it would need a little positive feedback.

The clock, BTW has been working very well for 4 years and is now really cool since I added power on and off time recording in non-volatile flash memory. The latest version displays 3 time zones, though the seconds count is shared between the 3 displays. Still need to implement the WWVB time reference with a Galleon receive module.

GG

I found that just a resistor across the secondary pretty much cures ringing, at least better than capacitors across the diodes. Choose R to be as small as possible with dissipation and transformer current in mind. With 14V~ 1k should be sufficient for a 10VA tranny.

--
ciao Ban
Apricale, Italy

And a burned-out transformer. ;-)

Best regards, Spehro Pefhany

--
"it\'s the network..."                          "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com

Right, that's a lot cleaner. As regards recovering a timekeeping clock off the AC line, the ct transformer is easy but the ungrounded bridge is a nightmare.

With the grounded ct, you can still sometimes see impressive diode reverse recovery spikes.

John

ringing,

Yep. Same here!. And UF4001's etc for the occasional tricky-dicky, circuit arrangements. Wish LTspice had a realistic transformer model. A good one can be done manually but the resulting diagram fills half the screen and looks nothing like a transformer. john

See...

Newsgroups: alt.binaries.schematics.electronic Subject: 2-Input Comparator From S.E.D - SED2InputCompSolution2-XFMR.pdf Message-ID:

I just threw in 1N4006's. Are they "fast"?

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

--
Hello, Helmut.

I don\'t think there\'s anything wrong with my scope since, when I
switched over to 1N4002\'s, the spiking was readily apparent on my
HP54602B and even on my Tektronix 2215A.

Check this out:

news:fs8m72h70p19860r3hhgckrdliu75m4lm1@4ax.com

& == ampersand @ == "at" sign (If anyone knows a different name for that one, I'd like to hear it.)

Thank you. I can see you having an excellent future as a grammar-school English teacher.

Design any cool electronics lately?

John

Full name: "commercial at sign".

For '.', we have "period", "dot", "full stop" and "full point".

Best regards, Spehro Pefhany

--
"it\'s the network..."                          "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com

Just use an R/C filter ahead of a 555 timer... it'll absorb all kinds of ratta-tat-tat.

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

My ISP's dropped binaries support sadly.

Certainly not.

Graham

RYO model.

I did a linear supply ten years back with a series FET that switched the main cap + regultaor in/out if the dV across LT200 was too high. That was when I first looked at conventional rectifier "snubbing", using only caps. Of course that doesnt work very well, as all it does is move the energy around. A single RC damper across the AC input to the rectifier worked extremely well.

Cheers Terry

Depends on capacitive and DC leakage terms, when diodes are not conducting fully.

RL

At either end of the secondary relative to what? You might develop enough one day to realize that this is exactly a diode bridge analog switch with DC off bias arrangement. Most people want to know the winding voltage wrt the common on the DC side, may be a mistake to assume the diodes standoff equal voltages- better to go with Is*(exp(-V/Vt)-1)- or swamp the diode Is with a resistor divider. The rectified waveform is a very bad one for a line clock reference.

You are a little late to the party, and you didn't even bring a gift.

John