Unusual functions of cheap parts
in [Design]
|
Prev: Op Amp Calculations
Next: 6v & 90v DC Power supply
From: David DiGiacomo on 27 Nov 2005 00:23 In article <4388fc27$0$20854$9b4e6d93(a)newsread2.arcor-online.net>, Henry Kiefer <otc_friend(a)gmx.net> wrote: >Bob Pease of National Semi mentioned a ONE AND ONLY transistor circuit >above/under voltage rail converter (with detailed theory). I cannot remember >the details. But interesting if sometime a slightly voltage behind the power >rail is needed. For example to power a CMOS Opamp now doing rail-input. For a good discussion of Bob Pease's "April Fool" negative voltage generator, see: http://www.edaboard.com/viewtopic.php?p=423522 Unfortunately you have to log in to the site to see the drawings & photos. I don't think it produces nearly enough current to power an opamp.
From: Adrian Tuddenham on 27 Nov 2005 03:40 martin griffith <martingriffith(a)XXyahoo.co.uk> wrote: > On Thu, 24 Nov 2005 09:40:27 +0100, in sci.electronics.design "Henry > Kiefer" <otc_friend(a)gmx.net> wrote: > > >Hi all - > > > >After my first thread going from "standard" cheap parts for up to vhf > >frequency to a discussion about the usefulness of Spice simulator...... I > >try it another time hopefully get attention of frustrated co-readers: > > > >For example the rechtifier diode 1N4007 can be used as a rf switching diode, > >for example as rx/tx-switch. This is because it is a pin structure diode. > >This type is cheap and you can get it almost everywhere. It shows good > >performance for the price. Surely for high-end you should do it with another > >type tuned to the application it is made for. But anyway it works in some > >circuits. > > > >Do you know of other interesting devices or circuits good for misuse? > > > >Best regards - > >Henry > > > Switching a 20 year old 24v weller soldering iron on and off is a good > test for seeing if an 8051 cpu board is EMC proof I have a 1940s pistol drill that will generate a spike big enough to trigger the central heating on from the next room. -- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk
From: Fred Bartoli on 27 Nov 2005 04:51 "John - kd5yi" <groups5MUNGE(a)verizon.net> a ?crit dans le message de news:dmb74501vks(a)enews2.newsguy.com... > > "Henry Kiefer" <otc_friend(a)gmx.net> wrote in message > news:4388fc28$0$20854$9b4e6d93(a)newsread2.arcor-online.net... > > Yes Martin. I've seen that and a refrigerator can it too! > > - Henry > > > > > >> Switching a 20 year old 24v weller soldering iron on and off is a good > >> test for seeing if an 8051 cpu board is EMC proof > >> > >> > >> martin > > > > > But, it's a bit easier to degauss your picture tube with a soldering gun > than with a refrigerator. > And also take a bit less space on your bench :-) -- Thanks, Fred.
From: Matthias Weingart on 27 Nov 2005 04:57 Martin <martin.lenz(a)gmx.at> wrote in news:ops0vsn10r8lri9x(a)news.gmx.at: >> To save power, use the LEDs of a backlight to measure the ambient >> light to decide to switch the backlight on or not. >> > But how to decide to switch it off? I think there you have to > sample - switch of for a short time and test. This could give a > flickering backlight. Ok, you found the skeleton in the closet. :-) You can not use this method to switch it off - but it is not required in most cases. Think of a cell phone - the backlight goes on every time you press a key, and it is going off after 10 seconds. M. -- Bitte auf mwnews2(a)pentax.boerde.de antworten.
From: Martin on 27 Nov 2005 08:06
Am Sun, 27 Nov 2005 09:57:23 +0000 (UTC) schrieb Matthias Weingart <mwnews(a)pentax.boerde.de>: > Martin <martin.lenz(a)gmx.at> wrote in > news:ops0vsn10r8lri9x(a)news.gmx.at: > >>> To save power, use the LEDs of a backlight to measure the ambient >>> light to decide to switch the backlight on or not. >>> >> But how to decide to switch it off? I think there you have to >> sample - switch of for a short time and test. This could give a >> flickering backlight. > Ok, you found the skeleton in the closet. :-) You can not use > this method to switch it off - but it is not required in most cases. > Think of a cell phone - the backlight goes on every time you press a > key, and it is going off after 10 seconds. OK, so you can decide to not switch it on and save some mAs. -- Martin |