STEREO ELECTRET MIC PREAMPLIFIER CIRCUIT SCHEMATIC DIAGRAM

STEREO ELECTRET MIC PRE AMPLIFIER CIRCUIT SCHEMATIC DIAGRAM
For maximum performance, use solid capacitors or film capacitors and metal film resistors.

FM WIRELESS MICROPHONE CIRCUIT SCHEMATIC DIAGRAM

FM WIRELESS MICROPHONE CIRCUIT SCHEMATIC DIAGRAM

The range of frequencies for the FM broadcast band is 90MHz (MHz = Megahertz or 90 million cycles per second). Because the FM microphone has a variable tuned circuit, it can be tuned to a quiet spot on your local FM broadcast band for the best reception. When the small microphone element is struck by sound, it converts the audio to a change in current through resistor R1 (see schematic diagram).

DYNAMIC MICROPHONE AMPLIFIER CIRCUIT SCHEMATIC DIAGRAM

DYNAMIC MICROPHONE AMPLIFIER CIRCUIT SCHEMATIC DIAGRAM
Dynamic microphones are versatile and ideal for general-purpose use. They use a simple design with few moving parts. They are relatively sturdy and resilient to rough handling. They are also better suited to handling high volume levels, such as from certain musical instruments or amplifiers. They have no internal amplifier and do not require batteries or external power.

CIRCUIT PORTABLE MIC PRE-AMP SCHEMATIC DIAGRAM

CIRCUIT PORTABLE MIC PRE-AMP SCHEMATIC DIAGRAM
The circuit built based on a low noise, high gain two stage PNP and NPN transistor amplifier, using DC negative feedback through R6 to stabilize the working conditions quite precisely.

CIRCUIT LOW IMPEDANCE MICROPHONE AMPLIFIER SCHEMATIC DIAGRAM

CIRCUIT LOW IMPEDANCE MICROPHONE AMPLIFIER SCHEMATIC DIAGRAM
It will work with stabilized voltages between 6-30VDC. If you don’t build the impedance adapter part with T1, you get a mic-amp for higher impedance microphones. In this case, you should directly connect the signal to C7.