1-LED level meter - module

The advantages of 1x1 meter:

• it takes little place on the front panel
• it doesn't need a big description (-3dB, 0dB, +3dB)
• there's no problem with drilling equal holes
• it allows to asses the level of drive signal

Assessing the level of drive signal gives a clear indication:

• diode isn't lighting – the lack of the signal of the level is very low
• diode is blinking green – a safe bandwidth below -6dB
• diode starts lighting orange – a bandwidth between -6dB and 0dB
• diode lights red – 0dB and more, signal distorted in 100%

In general, when the diode isn't green, something bad happens.
The system bases on a popular double operational amplifier and bi-color green-red diode. Because to power the preamplifiers, voltage higher then 5V is often applied, there is a stabilizer LM317 on the plate. Potentiometer allows to decrease sensitivity and adaptation to specific application.




On the SMD plate, due to the availability, the potentiometer and the capacitor are threaded. They can also be fitted as SMD components, from the side of copper. The choice of LED is important due to the size. On the 3mm LED it is easier to get the orange color, on 5mm the colors green and red can be seen clearly separate.



Link to original thread (video and attachment) – 1-LEDowy wskaźnik wysterowania - moduł