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.
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