micro power square wave oscillator

You could actually do it with a single gate valve (single-pole-double-throw ;-)

...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

Obama-lackey! Obama-lackey! Boom! Boom! Boom!

Obama-lackey Wesley Clark opines:"He (McCain) hasn't held exe- cutive responsibility. I don't think riding in a fighter plane and getting shot down is a qualification to be president."

But being a small potatoes politician who's served only three years in the Senate does ???

Due to excessive spam, gmail, googlegroups, UAR, AIOE are blocked!

Yes, I agree. In fact, that is the only way I'd draw a schematic that I intended for ASCII posting. Let's me check out a few things to make sure I catch errors I should have known better about. (It won't help me fix things I'm ignorant about, of course.)

Well, if the glitch is simple enough I'd expect one to just expand the data display sufficiently to make the point clear. If it is something like an error where the context of the NTSC signal is also required, I'd suppose that would be a bit 'difficult.' But I've seen folks here struggling to draw up ASCII plots to make some point clear. Haven't you?

Jon

I don't really know. I installed it four years ago, and I haven't had to flush it yet. Of course there is already a lot of air dissolved in water from the Florida Aquifer. I have hat to flush other parts of the system because of rust. These are at the end of some long runs that don't get much use like a couple outdoor faucets at the back of the property.

Sure, but why add another valve I don't need? I'll take some pictures next time I'm out there. I have to move a few things out there to make room for my power chair, anyway. Since it will be in that corner, it'll be easy. To think, they laughed when I added outlets in that corner nine years ago. :)

Like a backwash valve? Then you must pay the pool equipment markup which can easily exceed 1000% ...

You can use the ASCII art character set in MS-Word for stuff like timing diagrams. But it does use characters above 127 so it may not work for all on Usenet.

I think the spring-loaded hammer-eliminator would be best, although I wonder if they would corrode?

...Jim Thompson

Good advice. I was thinking, assuming I consider doing anything at all, of using * and . and - and | and regular characters, generally. I didn't want to stray into special non-ASCII characters (which are

Jon

I've heard somewhere they last around 15 years. Good enough for me, they aren't that expensive. But installation would be a bear here.

Yes. I believe some people get a UTF-8 error otherwise.

The low capacitance of the fastest RF transistors might not be needed here; a more ordinary transistor (MPSH10) operated at super-low current might be good enough, cheaper, and less likely to go 200MHz crazy.

You're right of course that the modest 2n3904 could never manage the output swings you achieve here in that circuit at these power levels. That's why I had to dodge around it by keeping swings low.

BTW, your schematic looks great.

Fun.

Cheers, James Arthur

Cool program Jon. And yes, I love those 2n5179s. I was visiting the Bay area near Jameco once. The first chance I got I drove over, walked into Jameco and bought a bunch of stuff, including a load of PN5179s !

Cheers, James Arthur

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Drain the line every five or ten years. They've always worked for=20 me.

--=20 Keith

Ok, but then you need a valve up top. Put's you close to the cost of a real hammer arrester and after a few years it'll start leaking. And if little kids are around they might find that read handle of the valve an interesting "toy" ...

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Never bothered with the bleeder. They just worked. I tend to use=20 longer ones than the store-bought (silly expensive things)=20 arresters. They're burried in walls, so no handles.=20

--=20 Keith

Bill, that was a nice example of a classic circuit brought up to date with modern components. Nifty.

The output has an exponential rise with about a 4 uS time constant, partially from each collector load resistor's having to charge its associated Ct. That bit can be improved with the old diode isolation trick:

====== FIG. 1 ======

----+--------+--< Vcc R2 | R10 | 1M 1M | D1 | -||-+---|>|--+---> output Ct2 | |/ ---| Q1 |>. | === GND

Now when Q1 wants to turn off D1 allows R10 to "yank" the output up without having to charge Ct2.

Here's an extension of that idea:

====== FIG. 2 Improved Output Stage ======

----+------+------+--< Vcc | | | | +----- | ---> output R2 | R11 | | 1M 1M | | | R10 | | |/ 2M

-||-+----| Q10 | Ct2 |>. | '-----+ | |/ --| Q1 |>. | === GND

Q10 serves as a low-capacitance diode and also as a common-base gain stage that further squares up the output.

Risetime tau is improved to about 750 nS, and the output now swings rail-to-rail.

====== FIG. 3 Full Schematic ======

(LTSpice file appended below.)

I went 0.5uA over current budget--feel free to tweak it.

Nice circuit Bill--I had fun playing with it. Thanks.

Cheers, James Arthur

~~~~~~~~~~~~ Version 4 SHEET 1 2848 1276 WIRE -592 528 -752 528 WIRE -240 528 -592 528 WIRE -64 528 -240 528 WIRE 32 528 -64 528 WIRE -64 544 -64 528 WIRE 32 560 32 528 WIRE -592 576 -592 528 WIRE -240 592 -240 528 WIRE -752 624 -752 528 WIRE -64 656 -64 624 WIRE -592 704 -592 656 WIRE -464 704 -592 704 WIRE -384 704 -464 704 WIRE -240 704 -240 672 WIRE -240 704 -320 704 WIRE -128 704 -240 704 WIRE -464 736 -464 704 WIRE -240 736 -240 704 WIRE -752 784 -752 704 WIRE -64 784 -64 752 WIRE 32 784 32 640 WIRE 32 784 -64 784 WIRE -592 832 -592 704 WIRE 32 832 32 784 WIRE -512 880 -528 880 WIRE -464 880 -464 816 WIRE -464 880 -512 880 WIRE -448 880 -464 880 WIRE -384 880 -320 704 WIRE -320 880 -384 704 WIRE -240 880 -240 816 WIRE -240 880 -256 880 WIRE -208 880 -240 880 WIRE -32 880 -208 880 WIRE -208 912 -208 880 WIRE -512 928 -512 880 WIRE -592 1008 -592 928 WIRE -512 1008 -512 992 WIRE -512 1008 -592 1008 WIRE -208 1008 -208 976 WIRE 32 1008 32 928 WIRE 32 1008 -208 1008 WIRE -592 1040 -592 1008 WIRE 32 1040 32 1008 FLAG 32 1040 0 FLAG -592 1040 0 FLAG -752 784 0 SYMBOL RES -608 560 R0 SYMATTR InstName R1 SYMATTR Value 1meg SYMBOL res 16 544 R0 SYMATTR InstName R10 SYMATTR Value 2meg SYMBOL cap -384 864 R90 WINDOW 0 0 32 VBottom 0 WINDOW 3 32 32 VTop 0 SYMATTR InstName C1 SYMATTR Value 1.5p SYMBOL cap -256 864 R90 WINDOW 0 0 32 VBottom 0 WINDOW 3 32 32 VTop 0 SYMATTR InstName C2 SYMATTR Value 1.5p SYMBOL VOLTAGE -752 608 R0 SYMATTR InstName V1 SYMATTR Value 5 SYMBOL npn -32 832 R0 SYMATTR InstName Q1 SYMATTR Value BFR92A SYMBOL npn -528 832 M0 SYMATTR InstName Q2 SYMATTR Value BFR92A SYMBOL res -256 720 R0 SYMATTR InstName R3 SYMATTR Value 4.7meg SYMBOL res -480 720 R0 SYMATTR InstName R4 SYMATTR Value 4.701meg SYMBOL cap -528 928 R0 SYMATTR InstName C3 SYMATTR Value 0.68p SYMBOL cap -224 912 R0 SYMATTR InstName C4 SYMATTR Value 0.68p SYMBOL npn -128 656 R0 SYMATTR InstName Q10 SYMATTR Value BFR92A SYMBOL RES -256 576 R0 WINDOW 3 30 76 Left 0 SYMATTR InstName R2 SYMATTR Value 1meg SYMBOL RES -48 640 R180 WINDOW 0 36 76 Left 0 WINDOW 3 36 40 Left 0 SYMATTR InstName R11 SYMATTR Value 1meg TEXT -768 1176 Left 0 !.tran 0 150u 50u startup TEXT -776 1112 Left 0 ;This example schematic is supplied for informational/educational purposes only.\\nJuly 7, 2008 by Bill Sloman (but blame the Q10 output stage on James Arthur). TEXT -480 1176 Left 0 !.model BFR92A NPN(IS=0.1213E-15 VAF=30 BF=94.73 IKF=0.46227 XTB=0\\n+BR=10.729 CJC=946.47E-15 CJE=10.416E-15 TR=1.2744E-9 TF=26.796E-12\\n+ ITF=0.0044601 VTF=0.32861 XTF=0.3817 RB=14.998 RC=0.13793\\n+RE=0.29088 Vceo=15 Icrating=4m mfg=Infineon) TEXT 112 640 Left 0 ;Q2's collector is loaded by C2,\\nlimiting risetime. Q10 isolates\\nQ1's collector, allowing that node\\nto charge much more rapidly.\\n \\nQ10 doubles as a common-base\\namplifier stage, further squaring up the\\noutput from Q10's collector.\\n \\nThe new output is taken from\\nQ10's collector.\\n \\nJames Arthur, 9-Jul-2008

How come that whenever I want to import netlists like the ones in this thread into LTSpice I encounter an unknown syntax error? Upon "ignore" the traces will be there but all the devices are missing.

Those errors are from line wraps. Make sure the last 3 "TEXT" entries are each one-liners in your .asc file. That fixes it for me.

I modified one ouput and left one output virgin, for comparison.

HTH, James Arthur