Electronics Forum / Electronics / September 2005

Making a timer to switch off a soldering iron in a telephone exchange after
an hour. Irons are 50V Wellers fed from exchange battery. Timer prototype is
working fine but I'm hoping to get away from use of a relay to switch the
iron on and off, mainly because inexpensive small ...

I'm a legally-blind Finnish uni student majoring in information processing
science but have been interested in digital logic and symbolic machine
language for some time. Thus I took a uni course called digital techniques
which is dealing with digital logic, boolean and switching ...

Just wondering if anyone has purchased one of the DSE 120gb HDD DVD
recorders? - Tandy has them on special for $600 odd.
What are your thoughts?
Thanks in advance.

I walk down the alley on occasion, mostly looking at the pavement to
find 'road hazards'.  I've picked up a record 106 of them this summer,
but I usually average between 2 and 10, mostly nails and drywall screws.
I think my had the main reason I haven't had a punctured tire in a ...

Actually a repair problem for a low noise microphone pre-amp but seems to be
a general design flaw.
Pre-amp uses a Burr Brown INA103 very low noise instrumentation op-amp.
In this M-Audio Omni i/o preamp and an outline design application in the

I bought a tiny little 5.5" B/W TV set, and I thought it would be an
interesting thing to do to take the tube and try and build myself a
little computer monitor - nothing fancy, just a device to take TTL
horizontal and vertical sync signals and a video signal and give me a

The TC4420 & TC4429 seems to be mentioned a lot in overseas articles, but
again, no luck finding them in Australia??!!

A lot of years ago (38 to be exact) a wise old "rule of thumb" engineer
taught me a slick way of getting maximum gain out of an opamp without
resorting to very high or very low values of resistors.
As we all know, for an inverting opamp, the gain is given simply by Rf/Ri,

Greetings group.
Philips ctv model 32PW6516/75R.
This problem is very random.
Sometimes the ctv will not respond to the remote control, but it will

Amplifier, impedance and power?
The only specifications I have of my portable car amplifier are:
60 watts output
12 volts DC

Can someone explain how you would take a line level audio signal and
conver it to resistance in the range of 0 - 1 MOhm? Any help
appreciated...

I have a home wiring project that I need help with.  Actually I need
to find a device that can control a light, using power from another
light socket, and still letting a light be in that socket.
Ok.  I will explain.

Anyone get Elektor Electronics magazine
http://213.222.12.205/Default.aspx?tabid=27&year=2005&month=9&art=52895&PN=O
n
Hopeless NZ bookshops have not put it on the shelf yet,

I just found an old CDROM drive in my garage (Sony cdu5221) and would like
to tinker with it but I don't have a computer power supply. Could anyone
tell me whether these drives actually need both the 5V & 12V supplies? If
they do, is there some easy way of getting the 2 reference ...

Maybe someone could give me a definitive answer on this:
In my car I was using a 300-watt power inverter which provides power by
being plugged into the cigarette lighter plug.  The power inverter was doing
fine for years until I absent-mindedly plugged in a 500-watt electric teapot