Halving Pulse Width/ Pulse Width Division

Flip it over so that "on" time is controlled by the Discharge Pin, then invert the output. ...Jim Thompson

Can you use two 555s (or one 556)? If so, use one set at the repeitition rate to trigger the second one which determines the duration.

Yes, that's the plan I'm going with, thanks. I couldn't quite work out what Jim was getting at with his "try flipping it" suggestion. I'm sure it was immensely elegant, though, coming from Jim.

Like this...

Not elegant... just takes advantage of Discharge Pin being Open-Drain (or collector, depending on vintage). ...Jim Thompson

Hello, hello? What's going on here? I thought you'd ditched PSpice some years ago in favour of the vastly more "cost effective" LTS, Jim?

I don't like LTspice's schematic entry... as klutzy as using Paint

But I regularly test circuits generated in PSpice with LTspice... just click on the .CIR file and select "Open with" LTspice.

I also do that now with TopSpice (customer request that Spice models run on LTspice and TopSpice).

Which presents problems...

TopSpice didn't, until recently, cope with pins named +IN, -IN, etc (math expressions). TopSpice also doesn't know what ATANH means, and can't do a .DC LIN PARAM... :-(

LTspice overly linearizes many mathematical expressions and regularly barfs on anything that is really fast with a G-source.

(Besides PSpice is quite cheap NOW... I'm stopped "tithing" maintenance when the Cadence/OrCAD cretins stopped supporting PSpice Schematics and required using Crapture... gag me with serving spoon ;-) ...Jim Thompson

I'm impressed! Thanks for that, Jim.

You are quite welcome! ...Jim Thompson

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It's really not that bad. If you watch a video by Mike Engelhardt, the creator of LTspice, he shows you a lot of quick ways to draw the circuits. I am pretty used to it now and don't find it too clumsy.

LINK Please

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If someone will hold my hand and show me how to make an instructive video, I'll demo original crispy flavor PSpice Schematics, which will out-run anything you can buy today, at any price. ...Jim Thompson

Really, LTSpice isn't so bad, really not bad at all.

Common components, R, L, C, GND, net labels, wires are just one keyboard hit away. Rotating and flipping components is just ctrl-r and ctrl-e, F7 and F8 allow reorienting or dragging components around, without or with the wires moving along. The mouse wheel zooms in and out, centred on the cursor location.

I particularly appreciate how one can draw wires through components and all the straight bits that short the pins of any single component together will magically vanish when you're done. A real time saver.

Can you detail one or two features that are missing or clumsy in LTSpice, and how they are dealt with in PSpice?

Jeroen Belleman

It's all about the user interface... so many to describe, but one example, to move in PSpice just click on the object to highlight it and drag it to where you want... in LTspice, you have to hit F7, then click and drag the object... those extra steps are annoying.

And the create your-own-part graphics editor in LTspice is on a level with MS Paint.

As a simulator, LTspice is fast... very fast... if you don't mind subtle errors like non-linearities linearized. I use Alternate Solver to avoid such issues.

If anyone happens to be visiting the Phoenix area and would like a demo, come on by... after I get my office organized... it's still a pile of boxes. The library is about complete, so the office is next.

...Jim Thompson

For real annoyance, try LTspice on a Macbook. F7 requires a shift key and as for 'right-click' ... for that, you have to find desk space, a Bluetooth mouse, and some batteries.