a small doubt

[harshit agarwal]

how do this circuit work?

 

[Colin Mitchell]

Look on talkingelectronics.com website and Google for Flip Flop

 

[rickselectricalprojects]

That circuit looks like a two transistor oscillator.

 

[Sadlercomfort]

Here's a great animation so you can see it working, its all to do with the capacitors which switch the transistors.

One capacitor will charge as the other discharges, then vice versa.

Animation:
http://www.falstad.com/circuit/e-multivib-a.html


Detailed information:
http://www.electronics-tutorials.ws/waveforms/astable.html

 

[duke37]

Note that this circuit produces a considerable reverse voltage on the base/emitter of the transistors. This was OK on the early pnp junction transistors but the newer epitaxial transistors should be limited to about 7V. At 9V you may be damaging them.

A couple of diodes could be added to eliminate reverse current through the bases.