# 4 Peak voltage tester circuits using op-amp and 723

If you want to check the peak voltage of the signal to change at any time. Measuring with a multimeter will not do it. We recommend this circuit. It may help you.

Table of Contents

## Precision Peak voltage detector with a long memory time

We use this circuit The op-amp IC number CA3140 is the main equipment, acts as a voltage sensor that is accurate.

So It is a precision peak voltage detector circuit, and it remembers voltage value in a long memory time.

This circuit is used with a positive signal input, when has negative feedback only. And the inverting input can only get some feedback when diode D1-1N4148 is forward biased. When we put the input signal is positive, the output voltage of op-amp increases equal to the inverting input signal.

In working, the capacitor C1 is charged to maximum voltage.

When the input is negative, the diode D1 will be reverse bias, the still voltage on the capacitor C1 but it is discharged slowly with an input current of the op-amp IC1 about 10pA.

Thus, this circuit can monitor a maximum (peak) voltage of more voltage signal and to remember them. For the following it with a multimeter.

## Dual limit comparator with LM709

This voltage comparator circuit gives a positive output when the input voltage is a positive or negative more than 8.5V.
But in between that the output is negative voltage.

The positive limit point is defined by the ratio of R1, R2, and the negative point by R1, R3.
The forward voltage drop across the diodes must be allowed from it before.

The output may be inverted by reversing the inputs to the operational amplifier IC1, that LM709 is used without frequency offset.

## Peak Detector by IC LF353

This is circuit Peak Detector voltage input, Use IC LF353
This be the circuit Peak Detector or checks pressure electricity topmost level is easily.

Which I uses integrated number circuit LF353 be the integrated circuit op-amp perform measure electricity pressure or , compare with the pressure there.

When see the circuit has already you will like. Because the equipment is a little and build easy. regard circuit idea well yes.

## Simple Peak Level Indicator circuit using LM723

You may like the Simple Peak Level Indicator circuit using LM723. In checking the sound signal level. We cannot use the normal meter for this case. We need to use the special tool.

I like to collect simple circuits and learn more. This is another one Peak Level Indicator circuit that interesting. It shows you know with the LED display.

Simple Peak Level Indicator circuit diagram

How it works
We often get an LM723 or UA723 to use as DC Voltage Regulator.

But this circuit can build the signal sound level checker circuit.

When we see in the structure in the integrated circuit, LM723.

It has the voltage detector, comparator, reference voltage, and more. Thus we can apply it to this working easily.

Note: In this circuit, I never build it. But I will show you. Because it is a good idea. If you have free time and love to learn more about the electronics, it may make you fun.

An audio signal comes to input through the preamplifier circuit. They include VR1, Q1, R1, R2, R3, R4, C1, and C2. They will increase the input signal to a higher signal to pin 5.

The reference voltage comes out of the pin 6 to a voltage divider, R5, R6. This voltage flows to pin 4, comparator.

In LM723 is non-inverting comparator. When Vin(pin5) exceeds Vref(pin 4), output switches from Low to High state. Thus LED1 will grow up.

This circuit can use the wide range voltage of power supply, 9V to 40V. Because of the limit current that controls with R8.

R7 is feedback to increase gain in IC.

VR1— adjust a signal level to input.

Get Ebook: Simple Electronics Vol-03

### 4 thoughts on “4 Peak voltage tester circuits using op-amp and 723”

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2. I am looking for a current peak detection, the application is 30amp ac power using a ACS 712 hall current sensor putting out 0-5 volts signal. I would like to regulate the peak output signal. Can you help?

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• Hi Habibidoost.
Thanks for your advice is helpful.

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