Electronics Forum / Basics / July 2008

I was reading the datasheet for the LM1875
http://www.national.com/ds.cgi/LM/LM1875.pdf
and I noticed that they do have a schematic for a single supply (as
opposed to a +/- supply).

I was charging my battery over the weekend and checked it last night
to find the battery dead as a doornail. Upon examination, the battery
is completely dry. I'm guessing it was overcharged and the water
boiled away but it shouldn't've 'cause it's an "automatic battery

i have doubt  to watch the movie in theatre and tv
In theatre's why all the lights r putoff, may be it will effect the
eye's  or any any other reason
and in home puton the lights and watch the tv

I bought a USB drive, and it came in a small plastic shell package.
Is it safe to assume that this plastic material is anti-static?
I have not yet opened the package, and I left it sitting on the carpet
for a while.  Then I did some vacuuming, and ran the vacuum cleaner

hi thanks for ur kind informaation which u have given,but i want to
know a small detail about  bridge rectifier.
DOES THIS BRIDGE RECTIFIER CAN BE CONNECTED TO THE 230VAC/50HZ
SUPPLY ,WITH OUT TRANSFORMER. DOES IT WITH STAND THAT VOLTAGE OR IT

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I found four 1N2071 diodes in my junk pile.  Apparently the 1N2071 is
an obsolete diode - Mouser doesn't carry it anymore.
I looked up the datasheet for the 1N2071.  It seems designed to
operate at 60 Hz, but didn't find any info on the maximum speed for

I would like to build 2 square wave oscillators from a 555 timer using
the classic R1/R2/C1 configuration. I would like them to have a 50%
duty cycle (or as close as can be) and operate at 30 and 60Hz
respectively.

Preserving our visual History and Data needs a robust format that will
be around for years into the future. After looking at all the options
digital Beta Tape as used by commercial TV Stations
should be the foundation of all modern archives. trying to keep up

My application is a programmable board+ high noise sound sensor+
speaker. First i need to know how can i purches compatible component
and from where can i bay it and how can i programm it.

I was hoping someone could explain how to do this calculation for me.
I've got 3 transistors and 5 RGB LEDs, and I need to use the
transistor to drive them, as my microcontroller can't source enough
current for all of them on one pin.

I am experimenting with a relaxation oscillator circuit consisting of
a NE-2 bulb wired parallel to a capacitor and this pair is wired in
series with a resistor and connected across a 150 V DC power source (a
bunch of DC wallwarts connected in series).  The resistor is variable

Can nichrome be soldered to nichrome?
Can nichrome be soldered to copper?
insula

Are the filiment support prongs in an ordinary household incandescent
light bulb made of Nickel metal or some type of Nickel alloy?
They look shiny like stainless steel.
I've been using them as points in negative ion generator experiments.

I'm looking for a circuit that can read a standard line level audio
signal and output a continous voltage 0-5v proportional to the
amplitude of the input.
This in turn would be read by an ADC/microprocessor  to modulate some