Here is an Electret Condenser Microphone – ECM preamplifier circuit based on ultra low noise BC650C transistors. Due to difficulty of finding BC650C, instead of them, as you can see in the schematic, ...

The circuit in Figure 1 can help if you must transfer dc power and audio over a pair of copper wires. One application for such a circuit is a low-cost door-opening system with speech input. The ...

Any modern phone call placed, voice recording captured, karaoke song belted or conversation amplified via hearing aid would not be possible without James West. West, now a professor of electrical and ...

There are different kinds of microphones, but they all do about the same thing, which is to turn acoustic sounds into electronic signals that can be amplified, modified, or recorded. When you speak ...