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Accurate 50Hz Oscillator Circuit Using 555 And 7490

electronicecircuits, May 12, 2010August 17, 2023
Accurate 50Hz Oscillator Using 555 And 7490

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.

Accurate 50Hz Oscillator Circuit Using 555 And 7490 IC 50 Hz
PARTS LIST
R12.2kΩ
R2142kΩ (120kΩ + 22kΩ)
R35kΩ PRESET
C10.001µF (102)
IC1NE555
IC27490 (SN74LS90N)
IC37490 (SN74LS90N)
IC47805 Regulator

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).

7490 SN7490A SN74LS90 SN74LS90N 7490N BINARY COUNTER IC7490 SN74LS90N 7490N BINARY COUNTER IC pin configuration

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.

50Hz Oscillator TEST Circuittesting 555 oscillator output50Hz Oscillator testing

Please send your ideas, which are very important for our success…

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Comments (10)

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  10. Bambang (Malang) says:
    April 14, 2013 at 2:39 pm

    Thank you good idea can help me to make 50Hz sine wave,and can you help me to give me schematic diagram frequency counter (4 digit only) ,please send to my email .Thank

    Reply

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