Multivibrator

dramrattan said:

Hi,

I attached a diagram of a multivibrator that generates beep tones for verification of a pin code. The pin code is entered by the calling party wishing to access an electrical device via a controller attached to the called party's telephone. The multivibrator for example will generate a single long beep tone if the pin code is correct and 3 short beep tones if the pin code is wrong.

I don't know what type of multivibrator is used here eg. if it is a astable, monostable or bistable. Which one is it and how do you know which it is?...I tried comparing the diagram to the standard configurations given for the astable, monostable and bistable from wikipedia after reading about each one but still don't know which type of multivibrator it is.

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Mikebits said:

Of course you meant the above shown multivibrator is an astable, as multivibes come in several flavors

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