555 Timer IC as a-stable Multivibrator
![555 Timer IC A-Stable Configuration (Figure A)](https://www.daenotes.com/daewp/wp-content/uploads/article-images/555-IC-a-stable-multivibrator-configuration_0.jpg)
A 555 timer IC is used a a-stable multivibrator as shown in the given figure (A). The threshold input is now connected to the trigger input (Pin 2), the resister R1, R2 and capacitor C1 for timing network which set the frequency of the oscillator.