OSD MX880 GEN2 4 Zone Amplifier 8Ch x 80W, Class D, Front Panel On/Off Buttons, Distributed Audio

Pyle 6-Channel Bluetooth Hybrid Home Amplifier - 1600W Home Audio Rack Mount Stereo Power Amplifier Receiver w/ Radio, USB/AUX/RCA/MIC, HD/OPT/COAX, AC-3, DVD Inputs, Dual 10 Band EQ - PREA90WBT

Fosi Audio BT20A Bluetooth Stereo Amplifier, 2 Channel Home Audio Component Amplifiers for Passive Speakers, Mini Class D Amp Receiver 200W for Indoor/Outdoor/Garage/Ceiling/Bookshelf Speaker

Transistor as Amplifier - Working, Circuit Diagram, Common-Emitter Configuration