DCA55 - Frequently Asked Questions (FAQs)
the DCA55 ok with germanium transistors, can it
measure leakage current and does it take into
account the leakage current for it's gain
The DCA55 will detect the germanium (or silicon)
type of semiconductor. It will measure leakage
current and it takes that leakage into account when
measuring gain (unlike most multimeter hFE
noticed the leakage current of my germanium
transistor gradually drop with each subsequent
measurement. Is my DCA55 battery failing or
something else wrong?
current is extremely temperature dependent and
particularly noticeable for germaniums as the
current is fairly high to start with. The leakage
current can double for just a 5°C increase in
temperature. So after some handling, the transistor
temperature slowly falls and can lead to a
decreasing leakage current. That's completely normal
and correct. Additionally, DCA55 test currents are
completely independent of battery condition.
Collector and Emitter of my germanium transistor is
showing the wrong way round, is the DCA55 wrong?
the leakage current of the germanium transistor is
quite high (due to warming from your fingers for
example), the DCA55 can reject the
"correct" pinout. However, it will then
search for all other device types and
configurations. It can, in those circumstances, find
a transistor with the C-E swapped (although gain can
be very low). Tests in a simple circuit confirm that
you can get a germanium transistor to work, with
some gain, in that way. So the DCA55 is not wrong,
it's just found a configuration that yields a low
leakage current. Try keeping your transistor cool
during testing to avoid this situation.
the Atlas DCA55 measure Zener diodes? Perhaps low
the DCA55 doesn't currently support Zener diodes.
Low voltage (<5V) zener diodes can lead to
confusing results although the displayed forward
voltage may represent the Zener voltage which can be
useful. Higher voltage Zeners (>5V) will be shown
as a regular diode and the forward voltage will be
the voltage of the pn junction not the zener
I use the DCA55 to match transistors?
The main parameters that you may be interested in
are hFE and VBE. Both of these
parameters are measured by the DCA55. This enables
you to group your transistors that have similar gain
figures for example.
will the DCA55 show if my component is faulty?
the DCA55 would show "Faulty or unknown
component". Sometimes it may still be able to
see a pn (diode) junction within the component
you're testing, in which case it would display
"Diode or diode junction(s)". If there is
a short circuit within your component then the DCA55
will display "Short circuit on RED GREEN"
my Atlas DCA55 be upgraded online?
only way to upgrade the firmware is to send your
unit to us. It's a very low cost process. Click
here to see how to order an upgrade.
is the latest version of the Atlas DCA55?
latest firmware version is 4.0x. This version adds
support for the new hardware version (backlight,
finer measurement resolution etc).
can't the DCA55 analyse triacs or thyristors that
need higher currents than 5mA?
test currents of the Atlas DCA55 are deliberately
kept below 5mA to avoid damage to any potentially
random component that can be connected any way
round. The Peak
Atlas SCR is aimed specifically at analysing a
wide range of triacs and thyristors that require
test currents from less than 100uA up to 100mA.
long is the warranty period?
our products now have a warranty of 24 months. This
doesn't cover accidental damage or abuse however.