- I removed the audio connectors to make space for new components
- two electrolytic capacitors from output were removed for the
same reason as above
- one resistor and one capacitor were also removed (see the arrows in figure 2)
- in place of above mentioned capacitor I made a strap (connection)
as you can see in figure 2 (upper arrow).
- additional components were added (according to figures 3 and 5)
- homemade probe was added. The cable was soldered directly to
USB module printed circuit board (PCB)
The components added at the input of module function as voltage attenuator (R1 and R2),
protection (R1, R3, D1 and D2) and AC component separation (C1). Because
of C1, we can measure only AC signals. As we have mentioned above,
we have built later a different hardware to add more
features compared to this one.
More details about software, calibration, instructions for use, links
and additional information (some applicable also for this oscilloscope)
can be found on next article .
Warning: This oscilloscope provide no galvanic isolation between its
inputs/outputs and USB interface. In other words, there is no electric isolation between
you and devices you measure (including your computer if the oscilloscope is connected).
Therefore, you have to pay attention for the voltages that exist in your
working environment. In some circumstances, this can cause
injuries to users or damage to the oscilloscope, computer or other devices.
In addition to observe all the applicable safety regulations, a good idea is to
check first with a multimeter the AC and DC voltages
between all the electric and electronic devices that you use in your activity.
Disclaimer: The information on this web site is provided "AS IS", without warranty of any kind.
The author has made the best efforts to ensure the design and the information provided are reliable.
Under no circumstances shall the author be liable for any direct, indirect, incidental, special
or consequential loss, damage, expense or injury incurred or suffered which is claimed
to resulted from use of this site, even if expressly advised of the possibility of
such loss, damage, expense or injury,
including, without limitation, any fault, error, omission, interruption or delay with respect thereto.
 - A more complex oscilloscope:
Oscilloscope with USB audio adapter 2