How I can make this sine to square wave converter accept higher frequency?

Because when I tested it, it only accepts 10KHZ max. I will need to input a higher level of frequency till 1000KHZ.

Would this mean that I need to swap the resistor values to lower values?

New to digital electronics. Would appreciate if someone could help. U1 is an Op Amp.

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  • 2
    \$\begingroup\$ You forgot to state what U1 is. \$\endgroup\$
    – Andy aka
    Apr 10, 2019 at 11:56
  • \$\begingroup\$ Oh Oops. U1 is Op Amp. \$\endgroup\$
    – Coolo
    Apr 10, 2019 at 11:57
  • 3
    \$\begingroup\$ There are thousands of opamps, fast ones and slow ones. But you use an opamp as a comparator, you might be better off using a comparator instead. Many comparators are designed for speed and faster than many opamps. \$\endgroup\$ Apr 10, 2019 at 12:07
  • 2
    \$\begingroup\$ That circuit has no components to intentionally limit its operating frequency. Any limit you are hitting is inherent to the opamp you are using. You need to name that opamp. Alternatively, you need to ask the question implicit in the information in the question. The better question would be "How can I build a circuit to convert sine waves to square waves at up to 1MHz?" \$\endgroup\$
    – JRE
    Apr 10, 2019 at 12:20
  • \$\begingroup\$ @JRE Ok, so do you think it'll be a good idea to post the question you have suggested and delete this post? \$\endgroup\$
    – Coolo
    Apr 10, 2019 at 12:31

1 Answer 1


If you want a fast sine=>square wave converter, redo your circuit around a schmitt trigger. A 74LS part would do. Does the 4000 series have one? I don't remember. Oh yes...4093.

  • \$\begingroup\$ Hi @Robert Endl, thanks for the reply. Got it, am I able to use 74LS14, Hex schmitt trigger inverter? \$\endgroup\$
    – Coolo
    Apr 10, 2019 at 13:43
  • \$\begingroup\$ I am limited to what my school can provide. My school does not have 4093. \$\endgroup\$
    – Coolo
    Apr 10, 2019 at 13:44
  • \$\begingroup\$ Sort of. 74 logic output doesn't swing rail to rail very well. 4093 is a cleaner solution. Or a 40HC93. \$\endgroup\$ Apr 10, 2019 at 19:16

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