ROSELJR

Originally I thought I could surf the Internet freely, but I heard others say that you still need to insert a sim card, which is a mobile phone card. Is this different from a mobile phone hotspot?

How to adjust the volume in the OPA2604 pre-amplifier? The potentiometer is located there I made a power amplifier, using TDA7294*2, but I used OPA2604 to control the volume, the sound quality is very good, the resolution is also very good, but the volume is unstable when controlling the volume, and there is a lot of noise! The sound is loud when there is noise! Please give me a picture. Thank you!

Hello, everyone, I want to ask can the UC3844 chip work normally with 15 volts on pin 7? Thanks in advance.