I am using a variac to control the
voltage going to a filament for heating
purposes. Does anyone know of a
way to control the AC current going to
this filament in an electronic fashion?
#04051 Paul Komarenko
or in-line with the cord, that would
detect current flow (typically about
four amps AC). Preferably the indicator
would be an LED or neon bulb.
#04052 Ron Sharpe
Regina, SK Canada
I thought I recently saw a ‘how-to’
article on how to build a home made
‘chip’ that increases the power in a
Cummins diesel, pick-up engine. It
modifies the fuel and timing curves.
One of them is marked "BRF-140-
0601 RF Module" and both have
headers with pins marked "T+", "ST",
"AI", "GN", "SQ", "DI", "AO", "R+", and
"CL". I've come up with several good
guesses as to the meaning of the
pins, but I'm hoping someone can
give me definitive answers.
Does anyone know who makes
this, or where I can find the data
sheet? Would these modules work as
two-way radio modems?
#04054 Jeff Bowles
In the winter time of northern
climates, it is a great advantage to
know if your car's 120 volt block heater
is actually working. Presently,
extension cords can be purchased that
have a lighted end that show the
presence of voltage. However, I am
looking for a simple circuit to build into
the male AC plug of the block heater,
I have a pair of RF modules
salvaged from a 900 MHz cordless
phone and the corresponding base.
[#1051 - January 2005]
I installed a homemade
electronic rear-view mirror in my
RV. I already had a 5” monitor and
connected it to a $39.00 CMOS
black-and-white camera. It works
fine, but the image is opposite from
a mirror view when viewed on the
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The solution to your problem is
as simple as reversing two wires
inside your monitor. The horizontal
yoke windings are what you need to
locate and transpose. The yoke will
have four wires, with continuity
showing between each of two
individual pairs. One is the vertical
deflection coil, the other horizontal.
The correct pair can be found by trial
and error. When the leads for the
vertical coils are manipulated, the
picture will be upside down, the
horizontal coils will "mirror image" the
picture. If you don't disturb the yoke's
mechanical position, no other
adjustments will be necessary.
If you wish to be able to simply
return the monitor to normal
operation without having to change
the wiring again, a simple switching
arrangement constructed with a
DPDT switch can be mounted on the
unit to facilitate this.
A caution if you go this route
though, don't switch while power is
applied to the monitor, or you risk