DCA55 - Frequently Asked Questions (FAQs)
the DCA ok with germanium transistors, can it measure
leakage current and does it take into account the
leakage current for it's gain measurement?
The DCA 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 measurements).
noticed the leakage current of my germanium transistor
gradually drop with each subsequent measurement. Is my
DCA 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
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
the Atlas DCA measure Zener diodes? Perhaps low voltage
the DCA 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 voltage).
I use the DCA to match transistors?
The main parameters that you may be interested in are hFE
and VBE. Both of these parameters are
measured by the DCA. This enables you to group your
transistors that have similar gain figures for example.
will the DCA show if my component is faulty?
the DCA 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 DCA will display "Short
circuit on RED GREEN" for example.
my Atlas DCA 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. We can upgrade
even the oldest units.
is the latest version of the Atlas DCA?
latest firmware version is 2.8 and 2.9. Both are current
versions (different numbers for two PCB manufacturing
streams). Version 2.8 added "digital
can't the DCA analyse triacs or thyristors that need
higher currents than 5mA?
test currents of the Atlas DCA 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.