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This circuit is a mono pre amp circuit, which can be used with a variety of inputs.Can be applied for extending the phone and the other with
When AF IN input signal to pin 3 of IC1, and The voltage input to pin 2 of IC1.The IC number LM741 used to amplifier circuit,Output at Pin 6.
And [...]

My Friend want circuit Temperature Monitor for control relay. I find on internet , See to This Web http://www.mitedu.freeserve.co.uk/Circuits good article circuit. The Temperature Monitor use IC LM741 or IC 301 for test Temperature control relay switch.
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Using a thermistor in the position shown makes a heat activated sensor. A change in temperature will
alter [...]

Low Pass Active Filter by LM741
When you want to filter low frequency gives can change only. I thinks the Low Pass Active Filter circuit help you. Because of it uses IC LM741,then usable easy follow circuit image. We can fix the frequency is cut off get, by equipment value R1=R2 = R , and C1=C2=C [...]