Sound Level Meter | Electronic Project Circuits

Posts Tagged ‘sound level meter’

Sound Source Locator Uses PreChamp

This circuit could be regarded as a simple alternative to the Sooper Snooper device featured elsewhere in this issue. It is based on the PreChamp preamplifier featured in the July 1994 issue of SILICON CHIP. It can be used to pinpoint or locate sounds coming from inconspicuous sources such as a noisy bearing in a VCR containing many bearings. Other examples are an audible gas leak or a puncture in a slowly deflating tyre, provided the background noise level is considerably less than the source noise.

The device uses an electret microphone. This is attached to the end of round Texta casing of the same diameter, then covered with spaghetti sleeving and overlapping the electret by 5mm to make it more directional. The electret was then wired to the two-transistor Pre-Champ preamplifier (available from Dick Smith Electronics, Jaycar & Altronics as a kit). The 2.2k? feedback resistor in the preamplifier is replaced with switch S1 and four resistors – 2.2k?, 4.7k?, 10k? and 22k? – to give gains of 23, 48, 101 and 221, respectively.

After passing through the modified PreChamp, the signal goes to the base of Q1 which is biased on the verge of turning on by the 100k? and 6.8k? resistors. When the electret microphone picks up a sound, the amplified signal is fed to the base of Q1 turning it on and drawing current via diode D1 to reduce the stored charge in C1, the 220?F electrolytic capacitor. This results in a dip in the reading of analog meter M1.

Meanwhile C1 is constantly being charged via the 10k? resistor and the 50k? trimpot VR1. VR1 is set to provide full scale deflection on meter M1 when no signal is present. If a 50uA meter movement is used it will required a suitable shunt resistor to suit the circuit. Summing up, as the unit is used to home in on a sound source, louder sounds cause the meter reading to drop. Frequencies below 20Hz will cause the meter pointer to flutter. Switch S2 and the associated 1k? resistor are provided to quickly discharge C1 to enable repeated measurements.
Author: P. Hetrelezis – Copyright: Silicon Chip

Be the first to comment - What do you think? Posted by admin - October 1, 2010 at 9:14 pm

Categories: Audio diagram, Meter Tags: sound level meter, sound synthesizer

Balance display circuit by BC147

This Balance display circuit,be the circuit shows the equilibrium in the sound in stereo system. By indicate that stereo system signal on the left and right have or not is a signal equal ? Which if signal both of channel left sound and right channel equilibrium or balance prevent. The LED bilateral switch off but conversely if 2 both of channel sounds are rough LED any one stick bright.
When one party power circuit. And input audio stereo signal into the input box if the left and right channel audio signal equal to the Q1 and Q3 the same stream. There was no difference in the LED voltage on both be ill. If the signal is not balanced. Hypothetical signaling through the right channel signal rather than left to the LED1 and LED2 light off signal indicating that the signal over the right-left channel.

Be the first to comment - What do you think? Posted by admin - June 17, 2010 at 4:18 am

Categories: Audio diagram, Detector, LED Flasher, Meter Tags: led dispaly level meter, sound level meter

Compares with sound level tool

A tool that use for fine to decorate the sound of , organ , piano , have the pitch is equal. By have the accuracy is similar to with compare with the sound of the professional. But use the ability in listenning sound beat. At happen between 2 frequency sounds that confute by use origin frequency pillar circuit in 250.830 kHz frequency occurrences. For feed to reach first part of 5 IC. Which build the circuit divides by the frequency model a program.