Switching circuit based on AC and DC input

[Murugesh_89]

Hi,
I want to design a circuit ( A ) with the following requirements.

For the AC input signal with the amplitude of ( 0v - 5V ) and frequency between 0 to 500 Hz is given to the circuit A - The output of the circuit ( A ) be Low ( 0 V ).

For the DC input signal with amplitude of 5 V is given to the circuit A - The output of the circuit ( A ) should be High ( 5 V ).

Please kindly help me to design this circuit..

Thanks,
Murugesh

 

[hamid159]

there are many ways to design the circuit...
first approach that came to my mind is if you could detect that voltage (either it is AC or DC )then you can make it.As in case of AC,there is some frequency..so you can do this by using frequecny detection method ( like frequency meter).if frequency is zero and input is 5V then output is high otherwise kept low.

 

[KlausST]

Hi,

One thing you should redefine:
0...500 Hz includes DC (= 0 Hz). I think you must define a low cutoff frequency.

Maybe 1Hz.

Then you need a lowpass filter ( cutoff lower than 1Hz) and a comparator to switch at the desired DCvoltage level.


Klaus

 

[Murugesh_89]

hi klausST,
the frequency range is between 75 - 500 hz