The USB Accessory Oscilloscope is a free Android application that allows users to view, measure, and capture waveforms in real-time. Developed by BYLi, this program is an improved version of Jeremy's Oscilloscope. This educational and reference app is designed to provide users with accurate measurements of frequency, Vpp, and DC offset. With a frequency range from 0.1Hz to 20kHz and input voltage from +/-1mV to +/-20V, the USB Accessory Oscilloscope offers a wide range of parameters to work with. The ADC resolution ranges from 8 to 10 bits depending on the sampling rate, which can go up to 50kHz. Moreover, this app comes with 16 different T/div from 5sec to 50us and 10 different V/div from 5V to 5mV. It is powered by a micro-USB cable and can also provide charging power to the Android phone/tablet.