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All Electronics Corp. ............. 7
AP Circuits .......................... 47
C2 Robotics ........................ 35
Command Productions ....... 35
Cunard Associates .............. 23
Dimension Engineering........ 65
Electronix Express .............. 34
E Tip Inc. ............................. 23
Earth Computer Technologies .. 6
ExpressPCB ....................... 59
Front Panel Express LLC ... 42
Futurlec ............................... 57
Images Co. ......................... 57
Lemos International Co. ......... 23
M.E. Labs............................. 19
MikroElektronika ................... 3
National RF.......................... 23
NTEPartsDirect ................... 43
NetBurner ............................. 2
NKC Electronics ................. 23
PanaVise ............................ 43
Parallax, Inc. ....................... 47
PCB Pool ............................ 42
Pico Technology ................... 5
Poscope ............................... 35
QKI TS .................................. 23
Ramsey Electronics ......... 82-83
Robot Power ....................... 23
Saelig Co. Inc. .....Back Cover
Technologic Systems .......... 11
Weirdstuff Warehouse ........ 23
AMATEUR RADIO
AND TV
National RF ................................ 23
Ramsey Electronics ................. 82-83
BATTERIES/CHARGERS
Cunard Associates .................... 23
BUYING ELECTRONIC
SURPLUS
Earth Computer Technologies ......... 6
Weirdstuff Warehouse ............... 23
CCD CAMERAS/VIDEO
Ramsey Electronics ................. 82-83
CIRCUIT BOARDS
AP Circuits ................................. 47
Cunard Associates .................... 23
Dimension Engineering .............. 65
ExpressPCB .............................. 59
Front Panel Express LLC .......... 42
Futurlec ..................................... 57
PCB Pool ................................... 42
Saelig Co. Inc. ............Back Cover
COMPONENTS
Electronix Express ..................... 34
Futurlec ..................................... 57
NTEPartsDirect ......................... 43
COMPUTER
Hardware
Earth Computer Technologies ......... 6
Weirdstuff Warehouse ............... 23
Microcontrollers /
I/O Boards
C2 Robotics ............................... 35
Images Co. ................................ 57
M.E. Labs ................................... 19
MikroElektronika .......................... 3
Parallax, Inc. .............................. 47
Technologic Systems ................. 11
DESIGN/ENGINEERING/
REPAIR SERVICES
ExpressPCB .............................. 59
Front Panel Express LLC .......... 42
Images Co. ................................ 57
National RF ................................ 23
PCB Pool ................................... 42
EDUCATION
Command Productions .............. 35
NKC Electronics ........................ 23
Poscope...................................... 35
EMBEDDED TOOLS
NetBurner .................................... 2
ENCLOSURES
Front Panel Express LLC .......... 42
KITS & PLANS
Earth Computer Technologies .......... 6
NetBurner .................................... 2
NKC Electronics ........................ 23
QKITS......................................... 23
Ramsey Electronics ................. 82-83
MISC./SURPLUS
All Electronics Corp. .................... 7
Front Panel Express LLC .......... 42
NTEPartsDirect ......................... 43
Weirdstuff Warehouse ............... 23
MOBILE RADIO MOUNTS
E Tip Inc. ................................... 23
PROGRAMMERS
C2 Robotics ............................... 35
Futurlec ..................................... 57
M.E. Labs ................................... 19
MikroElektronika .......................... 3
RF TRANSMI T TERS/
RECEIVERS
E Tip Inc. ................................... 23
National RF ................................ 23
ROBOTICS
Lemos International Co. ................ 23
Robot Power .............................. 23
SATELLITE
Lemos International Co. ................ 23
SECURITY
E Tip Inc. ................................... 23
TEST EQUIPMENT
Dimension Engineering .............. 65
Images Co. ................................ 57
NKC Electronics ........................ 23
Pico Technology .......................... 5
Poscope...................................... 35
Saelig Co. Inc. ............Back Cover
TOOLS
C2 Robotics ............................... 35
MikroElektronika .......................... 3
NetBurner .................................... 2
PanaVise ................................... 43
Poscope...................................... 35
July 2014 81
has the circuit installed. If it is less than
20 years old, it almost certainly does.
It is called the "battery indicator light."
That light does exactly what you want,
except it is dark when you want an
illuminated green LED.
Put the keys in the ignition and
switch to the ON position without
starting the engine. All the warning
lights on the dash should light up (this
is a bulb check routine to identify
burned out indicator bulbs or LEDs).
After a couple seconds, most of the
warning lights will go off, except
probably two. One is the oil pressure
warning light. The engine isn't running,
so the oil pressure is zero, so the light
is on. The other light still on will be the
battery light. The engine isn't running
so the battery is supplying all the
power to the truck’s electrics.
Now, start the engine. Those two
lights should go off. The battery light is
off which means the alternator is
supplying all the power to the truck’s
electrical systems. That little indicator
light basically just looks at the
electrical system's voltage. A good,
fully charged car lead-acid battery will
read 12.6V without any load. The
charging system of a car runs at about
13.5V to 14V.
You can check the voltages with a
voltmeter at the battery posts with the
engine on and off. If the electrical
system is at a voltage of 12.6V or
less, then the battery is carrying the
electrical load. If the electrical system
is at more than about 13V, then the
alternator is supplying all the electrical
power. If the battery needs charging,
then the alternator is doing so — as
long as the battery indicator light is
off. If the battery is not charging
because it doesn’t need to be, then
the light is also off. What the battery
light won’t tell is the charge/discharge
rate which you would need an
ammeter for.
Jim Sluka
Greenwood, IN