"Spehro Pefhany" schreef in bericht news: snipped-for-privacy@4ax.com...
some
Oops, you want a powerswitch. That will be $300 extra.
-- Thanks, Frank. (remove 'q' and 'invalid' when replying by email)
Aren't they just.
We could always do a belt and braces analogue of the temperature rise in the solenoid, complete with 'memory' and an emulation of heat loss.
NC
24V---+----+--------+-----+-----+-----+----o/o--->| | | | | __|__ | Sol+ [R1] [R2] | [R3] _|_ | | | | | | | D2/_\ |Relay|--+ _|_ | | | | |_____| D1 \_/ | | _|_ | | | |/e | D3\_/ +-----+ R1= 6k2 +--|pnp | | D4 | R2= 6k2 | |\ | +--+---|>|--+ R3= 12k | | |/ | | R4= 47k | | +--|npn | 24v | R5= 18k | | | |\e +-|+\| | R6= 20K | | | | | |Co>---+ R7= 10k | | | +----+-----|-/| | | | | | | | | | +---|--|>|----|---|----|---+ | _|_ | D5 | | | | | D5\_/ | | | | | | | | [R4] | | | | +---+---+ | | | o Sw1 | | | | | | / NC [R5] [R6] |+ | [R7] | o | /20k ===C1 | | | | | \ 20|000u | | | | | | | | | | |
0v----+----+-------+-----+---+----+---+->Solenoid-veWhen Sw1 is Opened, the relay is de-energised and applies 24V to the solenoid. D5 lifts the short off the 1mA c-c source, so C1 starts charging.
Roughly 300 secs later the voltage on C1 reaches 10.6V and the comparator output swings -ve, which energises the relay. Solenoid is de-energised. D5 shuts off the 1mA charging current and D3 pulls the +ve input of the comparator down to 0.7V.
The solenoid remains Off until the R3 has reduced the voltage on C1 down to below that 0.7V.
-- Tony Williams.
Oh buggerit! Shouldn't do late editing....
Typos corrected below. There's probably more.
~~
~~
-- Tony Williams.
Tony's circuit does this. It uses a constant current source.
Since I = C * dV/dt, if you keep the current constant, the change in voltage with time will be linear, ie, a ramp.
You could use one of those voltmeter LCD thingys to display the time left by doing a little interfacing. Getting it to display in seconds might be a challenge. An analog voltage meter would move the needle around, so perhaps you could change the reference card to display time rather than voltage?
--
Regards,
Robert Monsen
"Your Highness, I have no need of this hypothesis."
- Pierre Laplace (1749-1827), to Napoleon,
on why his works on celestial mechanics make no mention of God.
"Spehro Pefhany" schreef in bericht news: snipped-for-privacy@4ax.com...
You can try to overcome this security hole by taking a 5 minutes delay immediately after power up. Nevertheless, it's like copy protection. One day someone will find a way to circumvent this delay or what measure you ever take to prevent the equipment being used over 50% duty cycle. But then it sure will be done deliberately, not accidentaly.
petrus bitbyter
"Tony Williams" schreef in bericht news: snipped-for-privacy@ledelec.demon.co.uk...
[snip]Perhaps you could use an NTC on a nice heatsink, instead of a cap. Puts the environmental temperature into the emulation... A piece of aluminium with plenty holes in it, and a large bag of nuts and bolts, to calibrate the heatsink ;)
-- Thanks, Frank. (remove 'q' and 'invalid' when replying by email)
-- Do you know what you really want?
Amazing isn't it? You can either pay a fortune for a genuine tool, or a few bucks for a knock-off set from China or Taiwan that work well enough on most of them. My old car radio was held in with a bizarre
5-sided "hex key" ("pent key"?) that I machined up rather than pay the SOBs for the matching tool.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
Brass, M6, of course. :-)
-- Tony Williams.
thumbs
operate
operators are
time.
goes for
crane
panel.
with a
Management put
system.
the
factory
the
can't
to talk
you
would
Are you suggesting these dolts are too stupid to buy a matching screwdriver? They sell a "security" kit of screwdriver bits for about $5 in the local tool shop.
My vote for the worst is the drive-up intercoms at fast-food places.
Reminds me of a funny.....
Bob Widlar just hated the paging speakers spread throughout the National facility in Santa Clara.
His complaints were ignored.
So, one day, he showed up to work with a "plumber's helper" and some cherry bombs.
Place cherry bomb in "plumber's helper" cup, light fuse, then raise arm up and hold cup against ceiling speaker... instant relief ;-)
...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.
I read in sci.electronics.design that funster wrote (in ) about 'Help me solve this (ego) problem', on Mon, 4 Apr 2005:
It's a bit more than that. Because most of us haven't met, there is a bit of evolutionary-protective xenophobia. This usually only operates when some small trigger phrase or inference occurs. OTOH, some are stuck in a pathologically xenophobic mode and see a need to flame every newcomer. This is justified only about half of the time. (;-)
-- Regards, John Woodgate, OOO - Own Opinions Only. There are two sides to every question, except 'What is a Moebius strip?' http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
I read in sci.electronics.design that funster wrote (in ) about 'Help me solve this design problem PLEEEZ', on Mon, 4 Apr 2005:
Bit sets for all the known types are freely available from broad-line distributors and I think I saw a set in Sears-Roebuck when I was in USA last. Everyone should have one. (;-)
In UK, the ISCE doesn't advise user-accessible volume controls at all. But people hang blankets over the loudspeakers or poke holes in the cones.
-- Regards, John Woodgate, OOO - Own Opinions Only. There are two sides to every question, except 'What is a Moebius strip?' http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
Correction. Tony graciously pointed out to me in private email that his circuit is actually doing an exponential decay, due to the resistor parallel to the timing cap. Thus, my prior message is based on an incorrect understanding of the circuit, and should be disregarded.
--
Regards,
Robert Monsen
"Your Highness, I have no need of this hypothesis."
- Pierre Laplace (1749-1827), to Napoleon,
on why his works on celestial mechanics make no mention of God.
wrote
about 'Help
broad-line
in USA
at all.
the > cones.
I like three layers of bubble wrap held in place with Duct tape.
I read in sci.electronics.design that Clarence_A wrote (in ) about 'Help me solve this design problem PLEEEZ', on Tue, 5 Apr 2005:
Very possibly, but how do you reduce the sound output of a loudspeaker?
-- Regards, John Woodgate, OOO - Own Opinions Only. There are two sides to every question, except 'What is a Moebius strip?' http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
I read in sci.electronics.design that Terry Given wrote (in ) about 'Help me solve this design problem PLEEEZ', on Tue, 5 Apr 2005:
Because people who are not into audio think it's easy. It's not (usually) highly sophisticated but it isn't simple.
-- Regards, John Woodgate, OOO - Own Opinions Only. There are two sides to every question, except 'What is a Moebius strip?' http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
Yes, but on a more professional level than as friend... I never did go drinking with him ;-)
I worked a Philco-Ford Semiconductor in 1968, right next door to National. When Philco-Ford shut that facility I got my technician, Jim Foster, a job working for Widlar. Another former technician of mine, Jim Estep, also worked for Widlar, but via a separate hiring path. (At one point in time there were 5 "Jim's" in my group... see why I broke family tradition and named none of my sons James ... ?:-)
Widlar always seemed to mistrust me. I'd often show up over there to take Jim F to lunch, and Widlar would stand in his lab door so I couldn't go in ;-)
One of my associates was stopped, along with Bob, traveling in separate cars, for DUI. The cop let them go after it was determined that the cop's brother worked for Bob.
I debate about that. I don't know what to write about. My expertise is in ASIC's... does anyone care?
...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.
Just ignoring it works too. Oddly enough, many of the high-tech companies I have worked for have had appalling, unintelligible PA systems. Weird - why cant a company that manufactures picoJoule laser pulse detectors get a PA to work?
Cheers Terry
Aha! That must make me the world's penultimate expert, "things that didn't work". I've done more of those than you can count ;-)
But advice I will give... don't let mistakes destroy your zeal, just learn from them, and then, when you reach my age, you can reminisce and have a good laugh.
...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.
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