Using this electronic power limiter circuit the output of a power electronic amplifier AF may be limited when they are exceeding the predefined amplitude and frequency output signal, or the current.
Current through the amplifier is measured with the help of Rx. Drive transistor T1 and T2 volume limiter opens when the voltage exceeds 0.56 Rx falling on V limiter reduces AF input signal amplitude saturating it with a variable resistance formed by a photoresist (LDR), which is lighted LED D2.
Using the table below can be configured output filter on three areas of adjustment of output power amplifier.
The filter is mounted so as to protect against overloads speakers speaker at both low and at high frequency.