Archive for category: Audio and Amplifier

Digital Volume Control Circuit

Audio and Amplifier | By: Diagram mania

The heart of this digital volume controller DVC circuit is IC2 4067, 16-channel analog multiplexer. Because the 1kΩ has been connected between every input and output, the multiplexer can act like a potentiometer. The total resistance is 15kΩ . You can use different values for the resistor to obtain a different characteristic. The current consumption […]

Classroom Microphone System Circuit

Audio and Amplifier | By: Diagram mania

This audio amplifier circuit is useful in classrooms to reduce the strain of lecturing ,if the surrounding environment is noisy. It uses the power amplifier IC LM380 that gives 2 watts output which is sufficient in a confined area. The amplifier is portable and the whole circuit and the battery can be enclosed in the […]

Class A Preamplifier Circuit

Audio and Amplifier | By: Diagram mania

This class A preamplifier has been designed in a symmetrical structure. In the input differential stages we’ve used the dual transistors T1 and T2. Polarisation correction is essential because of the amplification differences and is assured with T12. P2 brings the output voltage to 0. For maximum performances, T7 and T9 surfaces must be in […]

Car Audio Amplifier TDA1557Q TDA1553Q

Audio and Amplifier | By: Diagram mania

This stereo audio amplifier is for car purpose and can deliver up to 2 x 22W using a single TDA1557Q or TDA1553Q IC from Philips. TDA1557Q TDA1553Q datasheet

AVC Automatic Volume Control Circuit

Audio and Amplifier | By: Diagram mania

The function of this automatic volume control circuit is to amplify signals without distorting its dynamic compression. The amplitude differences in the signal are levelled off and the disturbing effect vanish. With this tehnique, overcompensation in the volume is avoided. The circuit is used to automatically control the volume levels of cassette recorders, audio tape […]

AVC Automatic Volume Control Circuit

Audio and Amplifier | By: Diagram mania

AVC – The featured circuit controls a volume line automatically. It delivers an output voltage of approximately 4 volts peak to peak. This voltage remains relatively constant by input voltages ranging from several hundred milivolts to serveral volts. This electronic circuit is not highly recommended for Hi-Fi applications because its noise factor is way above […]

UM3561 Siren Generator Design

Audio and Amplifier | By: Diagram mania

UM3561 is an excellent ROM IC that can generate Multi siren tones simulating Police siren, Ambulance siren, Fire brigade siren and Machine gun sound. This 8 pin low power IC can work down to 2.4 volts. The UM 3561 is a low cost siren generator designed for use in toy applications. The IC has an […]

Electronic Cricket Sound Generator

Audio and Amplifier | By: Diagram mania

Why an electronic cricket Many people like the cricket sound specially if they live in a big town. This electronic cricket circuit works in pulses, so the battery life is prolonged, the current consumption is just 2mA. The electronic cricket schematic is very simple, it is build with CD4049 or CD4009 wich is CMOS Hex […]

Electronic Bicycle Horn Circuit

Audio and Amplifier | By: Diagram mania

This simple electronic bicycle horn circuit uses only one gate of a 4093 quad 2-input NAND Schmitt trigger, U1, conected in a simple, low frequency, square-wave oscillator circuit. The oscillator’s output, at pin 3, drives the gate of Q1. The drain of that FET drives a small horn speaker. Potentiometer R1 can be adjusted to […]

Electret Microphone Amplifier Circuit

Audio and Amplifier | By: Diagram mania

This article describes an compact electret microphone amplifier but you can connect dynamic microphones with low resistance. Electret microphones can be inserted in the same box with the amplifier, it only need 5 to 10V or 9V battery with a current consumption of just 1.5mA. Electret microphone amplifier circuit Electret mic amplifier pcb