FNIRSI-138PRO 2.4" TFT Digital Oscilloscope 2.5MS/s 200kHz Built-in PWM

The FNIRSI-138PRO is a pocket-sized digital oscilloscope designed for quick bench diagnostics and field repairs. For drone builders, it provides an immediate visual readout of PWM signals, ESC outputs, and voltage noise, helping troubleshoot flight controller or receiver communication issues without requiring a bulky desktop scope.

Key features

• Compact 2.4-inch TFT display for clear waveform readouts on crowded workbenches.
• Integrated PWM signal generator (1Hz to 80kHz) for testing servos, LED circuits, and simulating flight controller signal inputs.
• Supports Auto, Normal, and Single trigger modes with rising and falling edge options.
• Single-button auto-setup adjusts the time base and vertical scale automatically to display the measured signal.

Specifications

• Display: 2.4" TFT LCD (320x240)
• Sampling rate: 2.5 MS/s
• Analog bandwidth: 200 kHz
• Voltage range: ±40V (X1 probe) / ±400V (X10 probe)
• PWM output: 3.3V amplitude, 1 Hz to 80 kHz, 0-100% duty cycle
• Coupling: AC / DC
• Dimensions: 65x60x18 mm
• Power input: 5V via USB Type-C

This mini scope simplifies electrical fault-finding when dealing with noisy analog video lines, dead ESCs, or uncooperative receivers, providing concrete diagnostic data for complex FPV electrical faults.