There could be several potential issues that could cause the discrepancy you're experiencing between the expected and measured values on your Hantek DSO5102P oscilloscope. Here are a few things you can check:
Probe attenuation: Ensure that you have set the probe attenuation correctly on your oscilloscope. The probe attenuation setting should match the attenuation factor of the probe you are using. For example, if you are using a 10x probe, make sure the oscilloscope is set to 10x probe attenuation.
Probe compensation: Check if the probe compensation is properly set. Oscilloscope probes often come with a small screwdriver for adjusting the compensation trimmer capacitor. Use this to adjust the probe compensation for accurate measurements. Improper probe compensation can affect amplitude measurements.
Calibration: It's a good practice to regularly calibrate your oscilloscope to ensure accurate measurements. Check if your oscilloscope has a calibration procedure and perform it if necessary. Calibration ensures that the instrument is accurately measuring signals.
Input coupling: Verify that the oscilloscope's input coupling is set correctly. It should be set to AC coupling for measuring AC signals like sine waves. DC coupling can result in incorrect amplitude readings.
Signal generator calibration: Check if your signal generator is properly calibrated. If it's not calibrated, it could be generating a signal with incorrect amplitude.
Grounding issues: Ensure that the ground connection between the signal generator, oscilloscope, and the device under test is proper. Poor grounding can introduce noise and affect measurement accuracy.
Power supply issues: Check if the power supply to the oscilloscope and signal generator is stable and free from any voltage fluctuations. Unstable power supply can affect measurement accuracy.
If you have checked these factors and the issue persists, it might be worth contacting the technical support for your Hantek DSO5102P oscilloscope for further assistance. They will have a better understanding of the specific features and potential issues associated with your device.