Astable Multivibrator

Introduction: Astable Multivibrator

In this instructable I will show you how to make high frequency signal generator (about 10Hz- 3300Hz). This has many different uses from a signal generator to a motor speed controller.

Step 1: Parts

To make the signal generator you will need the following parts.
2x220ohm resistors
2x470ohm resistors
2x100k potentiometers
2x0.47uF capacitors
2x2n2222 transistors
a header terminal strip (optional)

You will also need a soldering iron and a hot glue gun (pliers and a vice are also helpful).

Step 2: Schematic

The circuit is relatively simple and is rather easy to put together.

Step 3: Solder and Hot Glue

It is fairly simple to figure out were to put the components so I won't go into detail in that. The pictures may give you some ideas. If you want to put the project in a box you will obviously want to place the potentiometers more conveniently.

Step 4: Finished

Have fun with your signal generator.Here are some videos, one operating a small transducer, then dimming an led, and last I send the signal to my homemade amplifier (I might make an instructable on that to) with the output connected to a large speaker.

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    7 years ago

    just wondering.. why the hot glue?


    Reply 7 years ago on Introduction

    I like to keep the components protected. It reduces the amount of stress applied to them and therefore there eliminates the chance of breaking a solder joint, and it also stops each rail (on the perfboard) from shorting out (if i have any wires lying around or things like that).


    Reply 7 years ago

    ic.. tnx i would worry it might prevent transistors from releasing any heat generated... then again.. i suppose this circuit doesn't generate too much heat :)


    Reply 7 years ago on Introduction

    I just tested it with the small transducer connected to one of the outputs, powered by two AA batteries. It draws about a max of 30 mA (at the highest frequency) so heat dissipation is not a real problem seeing as the 2n2222 transistors max collector current rating is about 800mA.