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Henry Kiefer November 24th 05 08:40 AM

Unusual functions of cheap parts
 
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



Stefan Heimers November 24th 05 01:07 PM

Unusual functions of cheap parts
 
Henry Kiefer wrote:


Do you know of other interesting devices or circuits good for misuse?


I never tried it myself, but I heard that some people abused opened memory
chips as cameras, back when CCD camera chips were too expensive for
hobbyists.

http://www.classiccmp.org/pipermail/...ay/042581.html

http://groups.google.com/group/comp....4b0f2d5c0b6da7


Jorgen Lund-Nielsen November 24th 05 05:30 PM

Unusual functions of cheap parts
 
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

R.Freitag November 24th 05 06:00 PM

Unusual functions of cheap parts
 
Henry Kiefer wrote:
[...]
Do you know of other interesting devices or circuits good for misuse?


Take away the hat of a 2N3055 and use it as a light sensor (sensitive).

Robert

Best regards -
Henry


--
'Vom Standpunkt eines Beamtenrechtlers aus betrachtet ist der Tod die
schärfstwirkenste aller bekannten, langfristig wirkenden Formen der
vollständigen Dienstunfähigkeit.'
aus: Kommentar zum Beamtenrecht.

John Larkin November 24th 05 06:04 PM

Unusual functions of cheap parts
 
On Thu, 24 Nov 2005 09:40:27 +0100, "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



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




CA November 24th 05 06:20 PM

Unusual functions of cheap parts
 
Do you know of other interesting devices or circuits good for misuse?

The LM317 as a radio transmitter

http://web.telia.com/~u85920178/tx/317-tx.htm



John Larkin November 24th 05 06:22 PM

Unusual functions of cheap parts
 
On Thu, 24 Nov 2005 18:30:06 +0100, Jorgen Lund-Nielsen
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



Jim Thompson November 24th 05 07:11 PM

Unusual functions of cheap parts
 
On Thu, 24 Nov 2005 09:40:27 +0100, "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.

[snip]

Best regards -
Henry


That's an interesting use of the 1N4007. I've not tried that, what
kind of off capacitance do you get?

...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.

Boris Mohar November 24th 05 07:33 PM

Unusual functions of cheap parts
 
Cadmium sulphide ( CdS ) LDR as a Beta radiation detector. Not sensitive to
Gamma radiation which can be an advantage because it will detect Beta in
presence of Gamma. You have to paint it black. Horrible temperature
sensitivity but you can use another CdS as reference.



Regards,

Boris Mohar

Got Knock? - see:
Viatrack Printed Circuit Designs (among other things) http://www.viatrack.ca

void _-void-_ in the obvious place



John Larkin November 24th 05 07:42 PM

Unusual functions of cheap parts
 
On Thu, 24 Nov 2005 18:20:57 GMT, "CA" wrote:

Do you know of other interesting devices or circuits good for misuse?


The LM317 as a radio transmitter

http://web.telia.com/~u85920178/tx/317-tx.htm


Cool. 3T regulators, 317 and LM1117 types, can be neat power amps, for
driving unipolar loads like motors and such. Sort of a follower with a
largish offset.

Hmmm, an LM1117 followed by a monster darlington becomes a
super-follower with roughly zero offset.

John



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