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100 December 2006
Does a sound level meter record
transient sounds as well as higher
amplitude sounds originating from a
fundamental frequency? In other
words, if I strike a pan or piece of
wood, the impulse excites some fundamental frequency along with transients.
The amplitudes of the various transients
have varying amplitudes and usually
some "fundamental" frequency which
may have a higher amplitude. Do the
various frequencies "add up" along with
the fundamental (within frequency
range of an SPL meter) to produce a
reading in dBs? I am not certain how
the SPl meter is working in reference to
the entire frequency spectrum excited
by the impulse. Can someone explain?
I have a 12V 20W-halogen light
that I want to use in my car by plugging
it into the cigarette lighter receptacle.
The alternator produces 13.8V to
14.1V. Can I just connect the cord to a
cigarette lighter plug or do I need to
reduce the voltage to 12V? If I need to
reduce the voltage, could someone
suggest a circuit that I can fit into the
cigarette lighter plug?
#12062 Kenneth Larsen
I want to build an inexpensive, simple, audio transmitting and receiving
system (separate units) that can be
connected to the stereo minijack
output on an audio device/computer/
etc., and the receiver connected to
speakers that have a stereo minijack
input. I would like to have mutiple (3)
receivers. I need a schematic for both
the transmitting and receiving circuits.
How do I interface a VGA monitor
to use as a color monitor with ordinary
I need a 16-pin TCA280AI to repair
an auto body spot welder. It is a general-purpose trigger circuit. Are there any
companies that will sell me this chip without having to pay the typical $200 to
$500 minimum fee for a $15 to $20 chip?
#12065 Dave Stypula
As I travel the highways, I often
wonder if the road is going up or down
and by how much. One reason is that I
might typically shut the air-conditioning
compressor off when going uphill to
save energy, but turn it on when going
downhill as the engine is idling and the
energy to drive the air-conditioner is