I have just fried the STM32, while I was testing a digital amp. The amp had an output of ~5Vpk (600Hz sine wave) and was connected to a 8 ohm speaker. I connected the probe to the positive and the ground to the negative output of the amp, which was a mistake big enough to destroy the oscilloscope immediately. It was a mistake but I was still a bit surprised.
I am just not very used to working with oscilloscopes and realize that it is not okay to treat them like multimeters.
However, I am planning to order another DSO Shell from Banggood and have a question: Would I damage the DSO Shell(with voltages up to 35Vpk) during testing, if I connect the ground to the negative lead of the digital amps power supply?
Testing the signal shape of amp outputs (fed by a sine wave up to 100w) will be the most extreme thing, which I will do with an oscilloscope.
Damaged the STM32
Damaged the STM32
Last edited by aiyiadam on Fri Dec 21, 2018 10:00 pm, edited 1 time in total.
Re: Damaged the STM32
Let me also add a photo of my genuine DSO Shell and ask one more question: What is the DC rating for the C1?
Thanks
Thanks
Re: Damaged the STM32
Did you use a power supply that shared the same ground with the amplifier? If ground is isolated 35Vpk signal shouldn't damage the scope.
C1 is rated at 50V DC.
C1 is rated at 50V DC.
Re: Damaged the STM32
Thank you for the reply.
It is a cheap TDA7492 amp board powered with a 4.74A Delta Electronics brick power supply. The negative of the power supply is referenced to the ground. And I was powering the DSO Shell with a powerbank (using a 9V step up USB cable).
I forgot to mention the very important point that I had bridged the outputs of the amp. The negative amp output was active and grounding with this output would probably damage any scope. People use differential probes for this.
If I use the amp ground (negative of the power supply) for the DSO, I could just test the amp outputs separately?
And regarding the C1: Could I use a 100n polyester cap with higher DC rating for C1?
It is a cheap TDA7492 amp board powered with a 4.74A Delta Electronics brick power supply. The negative of the power supply is referenced to the ground. And I was powering the DSO Shell with a powerbank (using a 9V step up USB cable).
I forgot to mention the very important point that I had bridged the outputs of the amp. The negative amp output was active and grounding with this output would probably damage any scope. People use differential probes for this.
If I use the amp ground (negative of the power supply) for the DSO, I could just test the amp outputs separately?
And regarding the C1: Could I use a 100n polyester cap with higher DC rating for C1?