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low input voltage amplifier

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yagtoby

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i have an input source which produces tiny voltage with amplitude 400mV P-P (sinusoidal) at 1 Hz. i need an amplification circuit to drive TTL/CMOS ICs (clock signal).
could somebody help me with a suitable circuit with max. 6 or 9Volts battery source.

regards
 
Diode clamp to ground so only the positive peaks go past the diode, single supply comparator(LM393 or LM339) with a threshold of your choice, and an open collector output pulled up to the Vcc of your choice. If you like you can amplify the signal before running it into the comparator. You can also alter the resistor network to do a Schmitt Trigger.

Remember ,"Google is your friend" and check those manufacturers application notes for circuit ideas.
 
Okay, well first off I personally wouldn't call 400mv p-p "tiny" but then I guess it depends on the application :)

If you were willing to use a split supply (like +/-9v) then it would be pretty trivial, a single comparator would get it done for you. Single-supply operation makes it a little trickier, but it's still not very tough.

well if it's only 400mv p-p then it's not going to forward-bias a diode for papabravo's idea. You might be able to build an opamp-based "super diode" circuit (simulates a diode with no voltage drop) but I'm not sure how much of a pain that would be to change for single-supply.
https://en.wikipedia.org/wiki/Super_diode

Normally in situations like this I will AC-couple the signal into a resistor-biased comparator and be done with it. Since it's only 1Hz, that might not work out as well (might need a very big capacitor), but you could easily check it out with some simulation. The next closest thing would be to use an opamp summing circuit to add a DC bias to it (i'm assuming it's ground-biased now) and then pass it straight into a comparator.
 
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