It's not long enough or high enough of a voltage/current to do any damage.
But wouldn't it be safer to limit the test voltage to something under a capacitors reverse breakdown voltage of 1.5v?
You can't do that with a processor/circuit that is using 5V digital I/O pins.
@madires Looking on a scope during a capacitance test it seems that this tester will apply a high reverse voltage directly across the capacitor during one half of the cycle, which for an electrolytic is bad.
Should it be placing such a reverse voltage across the capacitor?
Below shows my scope which is DC coupled to the output of the tester with a 1200uF capacitor connected across it. Shouldn't this cause the capacitor to break down during one half of the test cycle?
What you saw seems to be some test for another component.
During the first phase a voltage of more than 300mV across the cap will end the test.
If you're concerned about running the other tests you could run the tester's in-circuit ESR measurement via the menu.
The atmega328 has version 1.11k according to the end of the self calibration routine.
The atmega328 has version 1.11k according to the end of the self calibration routine.Latest version should be 1.10k.
What you saw seems to be some test for another component. During the capacitance measurement the polarity of an electrolytic cap might be reversed, but the current is limited to 7mA and 10ms pulses.
During the first phase a voltage of more than 300mV across the cap will end the test. The test for small capacitance limits the voltage to the internal bandgap reference (ATmega168/328: 1.1V).
So it shouldn't be doing the test displayed on the waveform? The atmega328 has version 1.11k according to the end of the self calibration routine.
What is the procedure to access this menu?
The tester runs several checks to detect the component type and the capacitor check is done at the end. What you saw isn't probably part of the capacitance measurement but some other test done before the capacitance check.
For the k-firmware it's a long key press (>500ms).
Would your "m" firmware 1.15m act any differently?
I can't seem to access it at all and holding down the button for too long gives a timeout error. Maybe the Chinese have started to disable that menu by modifying the code before flashing the uC.
I can't seem to access it at all and holding down the button for too long gives a timeout error. Maybe the Chinese have started to disable that menu by modifying the code before flashing the uC.
Then most likely you have Markus' firmware. Latest version would be 1.15m. Karl-Heiz's firmware has the version 1.10k.
I don't have an Arduino, but I'd be surprised if you couldn't. Have a look at this: .
That's a good idea! I always encourage contributors and users to send bug reports, add-ons, modifications and so on.
How about having a buzzer that gives a small chime when the component is done being tested like on the peak atlas series. I'm guessing all it would need is for one of the chips outputs to pulse high once or twice for a couple hundred milliseconds.