This is an active stereo tone control circuit using very well known op-amp IC of TL072. The circuit include mic pre-amp and mixer control. In this design, we have two inputs: one for line (stereo), one for microphone and has control of the three audio frequency (high/treble, medium and low/bass). It also provide balance control… Read More »
This is a simple audio pre-amplifier circuit using single transistor 2N3904. This easy circuit provides good gain to weak audio signals such as electret microphone. Use it in front of an RF oscillator to make an RF transmitter that’s very sensitive to sound. Power supply used for this circuit is wide range from 3VDC to… Read More »
Here is the dynamic microphone amplifier circuit diagram. This circuit should be perfect for dynamic microphone… 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… Read More »
This a simple stereo electret microphone pre amplifier circuit. The below design diagram is the design for single channel, but the design of PCB layout is for stereo design og electret mic pre amp. For maximum performance, better quality, use solid capacitors or film capacitors and metal film resistors (1% tolerance). schematic diagram:
This is the circuit diagram of low impedance microphone amplifier. The circuit designed for use with low impedance (~200 ohm) microphones. It will work with regulated voltages between 6-30VDC. If you don’t build the impedance adapter part with T1, you get a microphone amplifier circuit for higher impedance microphones. In this case, you should directly… Read More »
This is a low-cost and simple intercom circuit design. Some intercom circuits is build by applying integrated circuits. The circuit described right here utilizes 3 certainly transistors which easy to find on the electronic store. Even a newbie can assemble it on a piece of veroboard without difficulty. The circuit consists of a 3-stage resistor-capacitor… Read More »
The following diagram is the schematic diagram of 4 transistors FM transmitter circuit designed by Paul K. Sherby. Components List: R1,R2,R8 = 1K R3 = 100K R4 = 150K R5,R7 = 10K R6 = 220 ohm R9 = 10 ohm P1 = 5K trimpot D1 = 1N4002 Q1,Q2 = 2N3904 Q3,Q4 = 7001, NTE123AP C1… Read More »
Here the simple mixer circuit with 4 inputs and 2 operational amplifier (op-amp) modules: A basic mixer suitable for mixing microphones or even effects outputs. The overall gain from input to output is one if the pot related towards the input is full up. You can make this a net gain of ten (or any… Read More »
This circuit is a powerful three stage, 9V FM transmitter (Tx) with a range of up to 1 kilometer in the open. It uses an RF transistor in its output stage and two BC547″s for the first two stages. Distance of trans-mission is critically dependent on the operating Conditions (in a building or out on… Read More »