Accurate 50Hz Oscillator Circuit Using 555 And 7490
This circuit is a getting a 50Hz pulse. It comprises a 555 timer and two 7490 divide-by-ten counter chips 7490. Below 50hz oscillator circuit can give good accuracy.
|R2||142kΩ (120kΩ + 22kΩ)|
The 555 generates a frequency of almost 5KHz which can be adjusted by VR1. This pulse fed to one divide-by-ten counter IC2 (7490) which gives an output of 500Hz (500KHz/10=500Hz). This frequency of 500Hz is again fed to the next counter IC3 to get 50Hz pulse (5ooHz/10=50Hz).
To get accurate 50Hz pulse, the 5k preset has to be set.
The circuit works on a regulated supply of 5V.
If you reducing R2 (like 120kΩ), this circuit uses as 60Hz oscillator.
Please send your ideas, which are very important for our success…