TABLE OF CONTENTS The word multivibrator means a circuit that can be "switched" all-the-way on and then all-the-way off, something like a relay. Some run continuously, like the relay buzzer circuit on page 138, and some wait for external signals to either turn them on or off, like the latching relay on page 136. Instead of generating sine waves as an output, multivibrators usually generate square waves like the ones shown on page 135.
If a transistor can be arranged to have delayed negative feedback, similar to the relay buzzer example on page 138, it can oscillate continuously. This is called "astable," meaning not stable. That is, it will not remain in one state, but instead it flips back and forth between "on" and "off."
With a transistor, if the feedback was immediate, there would be n o oscillation. Instead, the "negative" feedback would simply decrease the degree to which the transistor would turn on, so it would only go part-way on and then remain with that partial status. In fact, this does happen with certain other types of amplifier circuits (to be studied later) but not with multivibrators. However, if the feedback is delayed enough for the transistor to turn on completely before the negative effect takes place, then it can go all-the-way on, and later that negative effect will make it go all-the-way off, just like the relay did when it had capacitor delay. (By the way, it...
