Telephone recording circuit | Next Electronics

An AC millivoltmeter - calibrated in dB - with a range of 30V down to 3mV full scale (80dB range) would be extremely useful. Attach a microphone (electret mic capsules are quite good), and you have a relative sound level...

Acoustic Field Generator Circuit

Referring to the simplified schematic in A, the audio frequency generator (AFG) consists of 10 relatively simple circuit elements. IC1-c and IC1-d are configured as unity-gain non-inverting buffer amplifiers. The summing amplifier, IC2-c, combines equal amounts of the left and...

MUSICAL TELEPHONE RINGER

The core component of the circuit is IC1, the AY-3-1350 melody synthesizer IC from General Instrument. IC2 is a TCM1512 telephone ring detector IC powered by the telephone line. The circuit operates when IC2 detects a ring pulse on the...

VERY SIMPLE TELEPHONE INTERCOM CIRCUIT

Tro telephones can be utilized as an intercom through the implementation of this circuit. Traditional rotary phones, particularly those that are non-electronic, may be the most effective for this purpose. Additionally, this method can also power handsets alone. The circuit designed...

Power Amplifier Mini 2W+2W by TBA820M

The circuit is designed to amplify telephone signals using a 2W+2W amplifier with an 8-ohm loudspeaker. It provides adequate sound output while maintaining good audio quality. The primary component of this telephone amplifier circuit is the IC LF351, which enhances...

Mini Audio Amplifier

This is a low watt audio amplifier with a different technique in design. The 1.8K resistor has been connected to output of the circuit instead of VCC line. The output power of the circuit is about 250mW on an 8...

Electronics Telephone Talking Circuit

This is the basis of electronics telephone sets. You can use it to replace the talking circuit of an old telephone set with new design, better noise rejection and reliability one. Also you can use it to build a telephone...

LM390 Bass Amplifier

This circuit is a mono audio amplifier that will boost low frequencies as you see at the frequency response. The circuit is suitable for driving a subwoofer speaker for example. The output power of the circuit is about 1 Watt...

Isolated Telephone Interface

There's not much to this circuit. The two RJ-11 jacks are set up to feed the telephone circuit through from the wall to the phone. The active signal for a single phone is on the red and green wires. Yellow...