adjustable level (maybe 30-40%) and
then going back to full brightness
again without pause. What would I
need to accomplish this effect?
#10047 Phil Combs
I need a converter to change
analog component video to S-Video
and composite video. I haven't found
a commercial unit to do this, so I want
to make my own. There is an IC from
Philips Semiconductor — the
TDA8501 — which looks like it would
do, but I can't find a place that will sell
a small quantity. Does anyone know
of a source?
[4046 - April 2004]
I need a timer to activate a
remote feeder once or twice a day
for a one minute period for several
days. No AC power is available.
Intermatic makes an Electronic
Programmable Timer that runs on a
single AA cell and has “hard” switch
contacts that can be used on 120-277
VAC, 28 VDC, or 12 VDC at 4 A. It has
six ON/OFF cycles that can be set for
every day or spread over the days of
the week. Go to www.intermatic
.com and do a search for EI20C.
Sales data and an instruction sheet
Port Orchard, WA
[5042 - May 2004]
I'd like a schematic of how to
connect a transmitter/receiver
made by www.radiotronix.com
and sold by Mouser Electronics to
use as a USB (v.1.1) wireless
transmitter/receiver for my printer
There are several problems here.
USB devices are packet based and
configuration and setup data are sent
in both directions. The PC needs to
send the printer the data that is to be
printed, but the printer also needs to
be able to send back various USB
device ID and status messages, such
as information about the printer’s
make and model number and
messages for "Out of Paper" or "Paper
Jam." So a transmitter on one side
and a receiver on the other side won't
be enough, since the communication
needs to be bi-directional.
Another problem will be that USB
devices (the Printer/Scanner) expect
to be connected to a USB host
Controller (or a USB hub). The host
controller is responsible for keeping
track of and controlling the various
states a device can be put into —
powered, configured, suspended, and
others. For more information on this,
a copy of the USB specification can
be obtained from: www.usb.
[7043 - July 2004]
I work in electronics repair.
Sometimes, we do not have
documentation for the equipment
and we have a problem identifying
SMT devices (like the SOT- 23 style)
that have only a device code — like
“R2C.” Is there some universal
standard for these codes and, if so,
where can I find them?
#1 I have at least a partial answer
to this question. I have five Excel files
detailing cross-reference numbers for
SOT transistors. Manufacturers
included are Siemens, Phillips, NEC,
Motorola, and National
Semiconductor. The files comprise
about 1.3 MB and I have placed them
on my website, www.bolingeng.
com/ nuts__volts.htm for Nuts &
Boling Engineering Associates
NUTS & VOLTS
#2 These three to six legged SMT
pigs were hatched by Phillips
Semiconductor back in 1971 and can
contain anything from one or more
diodes, bipolar transistors, or FETs to
digital gates and op-amps! As reverse
engineers, we have done a lot of data
book research on them. We have
several thousand of the one to four
digit stamping codes for these.
Unfortunately, they are on index
cards, rather than a reproducable list.
We have seen several lists floating
around, but they are skimpy and
usually confined to only a few
manufacturers. Readers can Email us
( firstname.lastname@example.org) and we will try to
tell you what the device is and provide
a manufacturer's number, if possible.
Incidentally, the R2C you used as
an example shows up as PNP
transistor SSTA70 made by Rohm,