OVERVIEW
A simple Class A audio amplifier circuit using 2x BC337 transistors. Created using chemically etched copper-clad PCB with SMT components. Works as a middle-man amplifier between phone and headphones/speaker.
TECHNICAL DETAILS
DESIGN NOTES
Class A amplifiers are known for their simplicity and excellent linearity, making them ideal for audio applications where sound quality is prioritized over efficiency. The BC337 NPN transistor was chosen for its availability, low cost, and suitable characteristics for small-signal audio amplification.
The PCB was fabricated using the chemical etching process with copper-clad board, allowing for precise trace routing necessary for the SMT components. Power is drawn directly from the phone via USB-C, eliminating the need for external batteries while maintaining portability.