Learning Electronics

Learning Electronics

Learn to build electronic circuits

Peak Indicator

Small, portable and experimental circuit, Simple unit

A simple circuit, peak indicator of tops of musical signal. Each time where the level of signal exceeds the level + 4dB, turns on led D1. It is useful in each channel of console of sound, in final amplifiers or in that other application, to we needed. With the prices of circuit, the indicate begins with levels above + 4 dB (1.25V rms). For adaptation in different levels of signal, we can use a trimmer, before capacitor C1.

Circuit Diagram:

Peak Indicator Circuit Diagram


R1 = 10K

R2 = 1.2K
R3 = 220K
R4 = 4.7K
R5 = 4.7K
C1 = 47uF-25V
C2 = 2.2uF-25V
Q1 = BC550C
Q2 = BC550C
D1 = Red LED


Source : unknown