| Author |
Message |
Ron G
Guest
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 Posted:
Sat Nov 26, 2005 1:21 am Post subject:
Re: Unusual functions of cheap parts |
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Our newspaper had an article on that.
Also, for model rockets, burning up an ordinary resistor can be used as a
super-cheap ignitor.
Best---
Ron
John Larkin <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in message
news:361co1pavjfi56f0kmrm8phrtb64g2kmvo@4ax.com...
| Quote: | On Thu, 24 Nov 2005 18:30:06 +0100, Jorgen Lund-Nielsen
jorgen.lund-nielsen@xxxxxxxxxxxxdesy.de> wrote:
Henry Kiefer 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
Tuner Switching Diodes like the european BA244 (NOT PIN-Diodes!) work
well as medium fast Step Recovery Diodes.
Jorgen
I know a guy who uses surface-mount resistors as explosive detonators.
John
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Robert Obermayer
Guest
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| Posted:
Sat Nov 26, 2005 1:35 am Post subject:
Re: Unusual functions of cheap parts |
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hi,
sorry if you didnt like everything, but sometimes some voilence against
parts that cost you half a day of time and gave you a bad headache while
troubleshooting is necessary...
For more useful things, FETs actually can work as quite useful
one-component HF oscillators if wires and connection points are properly
chosen.With a second transistor one can build a working shortrange AM
transmitter.
A rather useful (works perfectly for SMPS uses) AC current probe for a
scope can be made by using a small UI cored RFI filter coil from a
monitor, connecting its windings in series and terminating with a 1ohm
resistor, to which a coax cable with BNC connector is soldered to.
The wire you want to measure the current in simply is fed trough the
core one time.
This only gives quantitative measurements unless calibrated but can be
very useful if you cant afford a real current probe.
The known resonant royer circiut used for CCFL inverters can be used for
larger inverters if appropriate parts are chosen, and can produce some
high frequency/high voltage with a transformer from a old TV (with no
internal rectifier).
This has its uses, besides connecting it to a old light bulb that works
as plasma globe or connecting both outputs to a large neon bulb
[Bienenkorbglimmlampe], which simply looks very nice but also produces
lots of RFI, so dont run it for too long.
FET gate drivers make nice TTL output stages for function generators, as
these can drive rather high currents and are fairly robust.
If a slowly, steadily changing linear voltage is necessary (for ex.
confirming the linearity of something) a 10turn precicion pot copuled
with a slow syncronous motor (a old microwave oven has a nice 2.5u/min
one) by some tape (so it slips/breaks when the pot is at its endpoint)
works nicely. |
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Al
Guest
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| Posted:
Sat Nov 26, 2005 1:35 am Post subject:
Re: Unusual functions of cheap parts |
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|
In article <clieo1lq869ialc6um02omsfdt266dvr2c@4ax.com>,
Paul Keinanen <keinanen@sci.fi> wrote:
| Quote: | On Thu, 24 Nov 2005 18:49:24 -0500, Jon Yaeger <jono_1@bellsouth.net
wrote:
Take apart a couple of D cell carbon-zinc batteries.
Wash off the carbon rods. Put each in a wooden clothes pin and connect the
attached ends to the mains voltage (US customers only, please).
The problem is that the carbon rod conducts heat quite well, so after
a while, any wooden object will catch fire :-).
Tap the free ends of the rods together. Move them apart as necessary.
You must have quite slow fuses in 110 V land if you can do a reliable
ignition without blowing the fuse. For 230 V operation, I would
suggest using a current limiting resistor (such as a large heater) or
an inductance (such as fluorescent light ballast) during the ignition.
When there is a solid arc, the current limiter can be shorted out.
Paul
|
I would put a 100 watt lamp in series thereby limiting the current. I
would shave the ends down to points so they heated up rapidly. I put
them into a hollowed out fire brick and made a cheap furnace. Of course
don't look at it; it's like looking at the sun.
PS: I was 16 at the time ;-)
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Roy Lewallen
Guest
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| Posted:
Sat Nov 26, 2005 1:35 am Post subject:
Re: Unusual functions of cheap parts |
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Paul Keinanen wrote:
| Quote: | . . .
You must have quite slow fuses in 110 V land if you can do a reliable
ignition without blowing the fuse. For 230 V operation, I would
suggest using a current limiting resistor (such as a large heater) or
an inductance (such as fluorescent light ballast) during the ignition.
When there is a solid arc, the current limiter can be shorted out.
|
Aren't you in danger of damaging your eyes from the UV emitted from the arc?
Roy Lewallen, W7EL |
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Guest
|
| Posted:
Sat Nov 26, 2005 1:35 am Post subject:
Re: Unusual functions of cheap parts |
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|
John Larkin wrote:
| Quote: | A 1N4007 can also be used as a drift step-recovery diode and as a
plasma avalanche diode. Together, two can generate a kilovolt edge
with a 100 ps risetime.
GAASfets make good fast analog switches; they behave pretty much like
jfets.
Wide-open LDO regulators make nice resettable fuses.
Ferrite beads do all sorts of interesting stuff.
Power mosfets make good heaters, and TO-220 bipolar transistors make
nice temperature sensors.
LVDS line receivers are surprisingly good comparators, and *fast*
I could go on...
John
|
tell us more John
NT |
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Si Ballenger
Guest
|
| Posted:
Sat Nov 26, 2005 7:50 am Post subject:
Re: Unusual functions of cheap parts |
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On Fri, 25 Nov 2005 20:48:19 GMT, Al <no.spam@wanted.com> wrote:
| Quote: | In article <clieo1lq869ialc6um02omsfdt266dvr2c@4ax.com>,
Paul Keinanen <keinanen@sci.fi> wrote:
On Thu, 24 Nov 2005 18:49:24 -0500, Jon Yaeger <jono_1@bellsouth.net
wrote:
Take apart a couple of D cell carbon-zinc batteries.
Wash off the carbon rods. Put each in a wooden clothes pin and connect the
attached ends to the mains voltage (US customers only, please).
The problem is that the carbon rod conducts heat quite well, so after
a while, any wooden object will catch fire :-).
Tap the free ends of the rods together. Move them apart as necessary.
You must have quite slow fuses in 110 V land if you can do a reliable
ignition without blowing the fuse. For 230 V operation, I would
suggest using a current limiting resistor (such as a large heater) or
an inductance (such as fluorescent light ballast) during the ignition.
When there is a solid arc, the current limiter can be shorted out.
Paul
I would put a 100 watt lamp in series thereby limiting the current. I
would shave the ends down to points so they heated up rapidly. I put
them into a hollowed out fire brick and made a cheap furnace. Of course
don't look at it; it's like looking at the sun.
|
The current limiter I saw used a glass pie pan with pieces copper
metal on each side with salty water as the electrolyte. It would
start to steam some when in operation. The furnace was a small
clay flower pot with holes in each side with the carbon rods
sticking inside until they touched. |
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Phil Hobbs
Guest
|
| Posted:
Sat Nov 26, 2005 9:13 am Post subject:
Re: Unusual functions of cheap parts |
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|
Si Ballenger wrote:
| Quote: | I would put a 100 watt lamp in series thereby limiting the current. I
would shave the ends down to points so they heated up rapidly. I put
them into a hollowed out fire brick and made a cheap furnace. Of course
don't look at it; it's like looking at the sun.
The current limiter I saw used a glass pie pan with pieces copper
metal on each side with salty water as the electrolyte. It would
start to steam some when in operation. The furnace was a small
clay flower pot with holes in each side with the carbon rods
sticking inside until they touched.
|
As a boy, I used an electric teakettle as a ballast for a two-D-cell carbon
arc lamp--worked great.
Cheers,
Phil Hobbs |
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**THE-RFI-EMI-GUY**
Guest
|
| Posted:
Sat Nov 26, 2005 9:35 am Post subject:
Re: Unusual functions of cheap parts |
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|
I have also seen thermistors used as a self regulating thermal element
for a crystal oven.
Joe Leikhim K4SAT
"The RFI-EMI-GUY"
"Follow The Money"
Pooh Bear wrote:
| Quote: | John Larkin wrote:
TO-220 bipolar transistors make nice temperature sensors.
I like that trick. Esp the isolated tab type.
Graham
|
--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"
"Follow The Money" |
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Ralph Barone
Guest
|
| Posted:
Sat Nov 26, 2005 9:35 am Post subject:
Re: Unusual functions of cheap parts |
|
|
In article <no.spam-94A7B5.15482025112005@news.verizon.net>,
Al <no.spam@wanted.com> wrote:
| Quote: | In article <clieo1lq869ialc6um02omsfdt266dvr2c@4ax.com>,
Paul Keinanen <keinanen@sci.fi> wrote:
On Thu, 24 Nov 2005 18:49:24 -0500, Jon Yaeger <jono_1@bellsouth.net
wrote:
Take apart a couple of D cell carbon-zinc batteries.
Wash off the carbon rods. Put each in a wooden clothes pin and connect the
attached ends to the mains voltage (US customers only, please).
The problem is that the carbon rod conducts heat quite well, so after
a while, any wooden object will catch fire :-).
Tap the free ends of the rods together. Move them apart as necessary.
You must have quite slow fuses in 110 V land if you can do a reliable
ignition without blowing the fuse. For 230 V operation, I would
suggest using a current limiting resistor (such as a large heater) or
an inductance (such as fluorescent light ballast) during the ignition.
When there is a solid arc, the current limiter can be shorted out.
Paul
I would put a 100 watt lamp in series thereby limiting the current. I
would shave the ends down to points so they heated up rapidly. I put
them into a hollowed out fire brick and made a cheap furnace. Of course
don't look at it; it's like looking at the sun.
PS: I was 16 at the time ;-)
|
I used a 0.5 or 0.7 mm pencil lead gently torqued down across the
terminals of a regulated DC power supply. Set the current limit very
low, crank the voltage up all the way and increase the current limit
until the center of the lead starts glowing red. Due to the heatsinking
effect of the binding posts, the lead will always heat up the most in
the center, then the carbon will start to evaporate and the remaining
lead will gradually neck down in the center until it is glowing white
hot. As soon as the lead breaks in the middle, you convert from
incandescent to carbon arc lamp, which usually surprises everybody
watching. The arc is good for about 5 seconds until the voltage drop
across the arc exceeds the capability of the power supply. |
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Paul Keinanen
Guest
|
| Posted:
Sat Nov 26, 2005 3:56 pm Post subject:
Re: Unusual functions of cheap parts |
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On Fri, 25 Nov 2005 12:29:52 -0800, Roy Lewallen <w7el@eznec.com>
wrote:
| Quote: | Paul Keinanen wrote:
. . .
You must have quite slow fuses in 110 V land if you can do a reliable
ignition without blowing the fuse. For 230 V operation, I would
suggest using a current limiting resistor (such as a large heater) or
an inductance (such as fluorescent light ballast) during the ignition.
When there is a solid arc, the current limiter can be shorted out.
Aren't you in danger of damaging your eyes from the UV emitted from the arc?
|
Certainly.
I used arc welding glasses when conducing these experiments.
Some trivia:
In the silent film era, actors had eye problems due to the UV
radiation from arc studio lamps.
Most of the usable illumination from the arc lights is actually from
the glowing carbon electrodes.
"Automatic arc lights" used a solenoid in series with the arc to keep
the distance constant between the poles regardless of carbon electrode
burnout. I assume that if this is to be used with a AC arc light, both
the moving coil as well as the static coil should carry the arc
current.
Paul OH3LWR |
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Matthias Weingart
Guest
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| Posted:
Sat Nov 26, 2005 4:16 pm Post subject:
Re: Unusual functions of cheap parts |
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|
John Devereux <jdREMOVE@THISdevereux.me.uk> wrote in
news:8764qh82fw.fsf@cordelia.devereux.me.uk:
| Quote: | ehsjr <ehsjr@bellatlantic.net> writes:
Henry Kiefer wrote:
Do you know of other interesting devices or circuits good for
misuse? Best regards -
Henry
An LED as a shunt regulator. Also, as a varicap.
Ed
Also a photodetector that is insensitive to long wavelengths
(because of the high bandgap).
|
To save power, use the LEDs of a backlight to measure the ambient light
to decide to switch the backlight on or not.
M.
--
Bitte auf mwnews2@pentax.boerde.de antworten. |
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Murray
Guest
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| Posted:
Sat Nov 26, 2005 5:19 pm Post subject:
Re: Unusual functions of cheap parts |
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Frithiof Andreas Jensen wrote:
| Quote: | "Henry Kiefer" <otc_friend@gmx.net> skrev i en meddelelse
news:4385b3b1$1$27887$9b4e6d93@newsread4.arcor-online.net...
Do you know of other interesting devices or circuits good for misuse?
Unbuffered logic gates can make a really bad but still useful analogue
amplifier by adding feedback and bias.
E.G the CMOS 4007. See the old handbooks for a '100dB |
amplifier' based on a RCA chip - there was a wiring
error in that old description - IIRC it was 3800? -
whatever, the 4007 is the same chip.
Murray vk4aok |
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wa2mze(spamless)
Guest
|
| Posted:
Sat Nov 26, 2005 5:35 pm Post subject:
Re: Unusual functions of cheap parts |
|
|
| Quote: | You must have quite slow fuses in 110 V land if you can do a reliable
ignition without blowing the fuse. For 230 V operation, I would
suggest using a current limiting resistor (such as a large heater) or
an inductance (such as fluorescent light ballast) during the ignition.
When there is a solid arc, the current limiter can be shorted out.
Paul
|
Did you know that a carbon arc acts as a negative resistance? Run the
arc on DC and put an LC tuned circuit in series with the arc (coil of
heavy copper tubing) and you have a powerful oscillator. |
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wa2mze(spamless)
Guest
|
| Posted:
Sat Nov 26, 2005 5:35 pm Post subject:
Re: Unusual functions of cheap parts |
|
|
Henry Kiefer wrote:
| Quote: | 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
Take one P channel Jfet and one N channel Jfet and connect them |
in series so the two sources are together, connect the gate of
each transistor to the other one's drain. This is known as a lambda
connection, and if you plot the voltage vs current from drain to drain
you will see a negative resistance region, usually around 3v
(depending on the transistors). The circuit will work as a tunnel
diode oscillator up to 100-200mhz. |
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Jim Thompson
Guest
|
| Posted:
Sat Nov 26, 2005 5:35 pm Post subject:
Re: Unusual functions of cheap parts |
|
|
On Fri, 25 Nov 2005 22:13:38 -0500, Phil Hobbs
<pcdhSpamMeSenseless@us.ibm.com> wrote:
| Quote: | Si Ballenger wrote:
I would put a 100 watt lamp in series thereby limiting the current. I
would shave the ends down to points so they heated up rapidly. I put
them into a hollowed out fire brick and made a cheap furnace. Of course
don't look at it; it's like looking at the sun.
The current limiter I saw used a glass pie pan with pieces copper
metal on each side with salty water as the electrolyte. It would
start to steam some when in operation. The furnace was a small
clay flower pot with holes in each side with the carbon rods
sticking inside until they touched.
As a boy, I used an electric teakettle as a ballast for a two-D-cell carbon
arc lamp--worked great.
Cheers,
Phil Hobbs
|
I've used a light bulb in series with a rectifier to charge a car
battery (just make sure that line ground goes to chassis ground ;-)
...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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