Decibel Meter
The described circuit functions as a sound level detection system, capable of registering sound pressure levels between 60 and 70 dB. The initial sound capture is facilitated by an 8-ohm speaker, which acts as a transducer, converting acoustic energy into an electrical signal. The output of the speaker is a low-level audio signal that requires amplification for further processing.
The first amplification stage employs a transistor, which serves to increase the amplitude of the audio signal. This transistor can be configured in a common-emitter configuration to provide both voltage and current gain, ensuring that the signal is sufficiently amplified before it reaches the operational amplifier stage.
Following the transistor stage, the LM324 operational amplifier is utilized. This quad op-amp IC allows for versatile configurations, such as inverting or non-inverting amplification, depending on the specific requirements of the application. In this circuit, one section of the LM324 is utilized to further amplify the signal, enhancing the detection capability of the circuit.
The output of the LM324 can then be interfaced with additional circuitry, such as a microcontroller or an LED indicator, to provide visual feedback or to trigger further actions based on the detected sound levels. The design emphasizes stability and low noise, ensuring accurate sound level detection across the specified range.
Overall, the combination of the 8-ohm speaker, transistor stage, and LM324 op-amp creates an effective sound detection circuit suitable for various applications requiring sound level monitoring.The circuit below responds to sound pressure levels from about 60 to 70 dB. The sound is picked up by an 8 ohm speaker, amplified by a transistor stage and one LM324 op-amp section 🔗 External reference
Related Circuits
A spectrometer is an instrument used to view and analyze a spectrum of a specific characteristic of a substance, such as mass-to-charge values in mass spectrometry or wavelengths in absorption spectrometry, including techniques like nuclear magnetic resonance spectroscopy and...
This circuit is a wideband signal strength meter designed to respond to small variations in RF energy within the VHF spectrum. It is capable of detecting AM or FM modulation as well as a simple carrier wave. The circuit...
This is it. It's a STEREO LED LEVEL METER. It's the cheapest and best bar graph display available and best of all, it uses readily available components. You only need a handful of LEDs, 22 transistors, some resistors, diodes,...
This Time Domain Reflectometer (TDR) is based on a circuit design published in the Electronics Design magazine on October 1, 1998. It is a modified version by Tomi Engdahl, which has been tested with a wide variety of cables....
This circuit is used to measure the voltage on a 12V (nominal) lead acid rechargeable battery system. It was specifically designed for use in solar powered systems, but is general enough that it can be used for automotive or...
The timer U1 operates as a free-running oscillator at 60 Hz, providing trigger pulses to timer U2, which functions in monostable mode. Resistor R1 is fixed, while capacitor Cx is the capacitor being measured. The output of U2 is...