Peak detector

I tried the circuit below, but i couldn't make the output.. Plz help me with corrections.
In schematic:
Resistors - 10k
capacitor - I tried both 1uf and 10 uf
Diode - IN914
I applied 15v to the op-amp

See page 13 into this application note.

at what carrier frequency ??? Unity gain is 1 at 100 KHz ???

Remember peak detector is for AC not DC

What were you expecting? What is your input voltage and is it grounded to the reference return? This is essentially a 1/2 wave rectifier, referred to as a peak detector so if say you have a sine wave (doesn't have to be) of 1V peak (+) then of course it would be 1V peak (-) as well. The output cap should charge to iV peak assuming that the frequency isn't too high. I say that because the opamp has an internal resistance which forms an R/C time constant with the output cap. In the case say 1MHz, it may not work at all with a 10uF cap.

Also consider that the input voltage range for an LM741 is, at minimum, +/-12 volt ( +/-13 volts typical), and the output swing will be less than +/-15 volt (depending on output load).

Check the datasheet!

Ah good point about the input voltage. Some ICs (this may not be one, haven't checked the spec) will latch up if the input voltage exceeds the bias supply voltage by more than a diode. Latched up means it is either at the +V rail, or it is at the -V rail, and does nothing no matter what the input is. This is corrected when power is reset, but will come back if the original latch conditions exist.

Surely check this.

I forgot about latch-up -- I checked the datasheet and the LM741 claims "no latch-up".

Curious 555, when you say you get nothing what exactly is nothing? Also trace out the signals and show where the nothing begins. For instance what does the positive (+) terminal of the opamp look like on a scope (assume you have one) or even an AC voltmeter. Second what does the negative terminal (-) look line, then what does the output of the opamp look like. You need to furnish more that just, "Nothing."

Sorry for the late I haven't seen the question till now
yes this schematic has an error a capcitor at the output of op-amp must be put
100nf is match

and I have a scheme perfect for Mic
this schematic can give 5V output "level" at 50 mv peak to peak input
1V at 10mv peak- peak input - directly connect your Mic and measer the level of sound at output using DC-Voltmeter

Move the anode of D2 from ground, to the junction of the - input of the 741 and the 10K resistor.