U
Uriah
Guest
I really appreciate everyone's help in understanding some of the
problems I encounter.
I am working on one of those emergency lights that are in most
businesses. The ones with the battery that come on when the power
fails. There is a 6 volt battery wired to a transformer and a little
circuit. The light doesn't come on. The battery is good. The bulbs
are good. It has two transistors and a voltage regulator, a bunch of
resistor and diodes. I tested everything with my DVM and Huntron and
I see no faults. When I test the transistors with the battery hooked
up I get a 6VDC drop from Emitter to Collector. Does this mean that
the transistor is acting like a open switch? There is no voltage
between the base and emitor or collector. Can you generalize about
transistors like this? I am thinking that there is no drive to the
base and that is why the transistor is not conducting. This sound
right? Also, along the same line, there are some diodes that are also
getting this 6VDC drop when you measure them in either direction. Does
that show a problem with that diode? And... how would I go about
confirming that the voltage regulator is working? It is a LM340T5.
Thanks for all of the help.
Russ
problems I encounter.
I am working on one of those emergency lights that are in most
businesses. The ones with the battery that come on when the power
fails. There is a 6 volt battery wired to a transformer and a little
circuit. The light doesn't come on. The battery is good. The bulbs
are good. It has two transistors and a voltage regulator, a bunch of
resistor and diodes. I tested everything with my DVM and Huntron and
I see no faults. When I test the transistors with the battery hooked
up I get a 6VDC drop from Emitter to Collector. Does this mean that
the transistor is acting like a open switch? There is no voltage
between the base and emitor or collector. Can you generalize about
transistors like this? I am thinking that there is no drive to the
base and that is why the transistor is not conducting. This sound
right? Also, along the same line, there are some diodes that are also
getting this 6VDC drop when you measure them in either direction. Does
that show a problem with that diode? And... how would I go about
confirming that the voltage regulator is working? It is a LM340T5.
Thanks for all of the help.
Russ