Audio Signal Generator


Posted on Feb 7, 2014

A couple of cheap CMOS ICs are used to digitally generate audio sinewaves across a wide range in this compact battery-powered test instrument. The oscillator features both unbalanced and balanced outputs. I use signal generators of one sort or another all the time as I design and build circuits. They include a pair of simple oscillators; a transis


Audio Signal Generator
Click here to download the full size of the above Circuit.

tor oscillator for testing crystals, and a CMOS square wave clock source, built on a scrap of PCB. I also have a homebrewed RF signal generator which covers up to about 50 MHz in a dozen ranges, and an audio signal generator. For many years, I used a kit-built audio oscillator, a design from the now defunct Electronics Australia (EA) magazine. It used a couple of op-amps, and was stabilized with a thermistor. It worked, but it had some serious limitations. The output level would vary with frequency, and it was annoyingly microphonic. Knock it by accident, and it would make a "boinnngggg" sound over top of the wanted tone. The oscillator`s frequency also had a habit of drifting a little over time. The most critical limitation however was its power consumption. It seemed to gobble batteries! Whenever I went to use it again, the bothersome thing would require a (yet another!) new battery before I could begin to use it. Along with the one or two seconds it took to start up, a product of its thermistor stabilization scheme, I became sufficiently annoyed with it one day that I designed and built this simple CMOS-based version. The oscillator described here is now more than a dozen years old. After all that time, and some fairly heavy use, I finally replaced the original 9V battery I put in when I built it about six months ago. It draws a miserly 3mA at 9V, but it is possible to power it with any voltage from 3V to as much as 15V,...




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Video amplifier and video detector
    Soft Circuit Singing Pig with Wigs Part 2 Circuit
    Wingfoot 813 Circuit Description and Schematic Diagram
    nicd battery charger schematic
    UPS For Cordless Telephones
    ring generator circuit
    Sound and light control touch delay saving switch integrated circuit diagram



    Top