However many of us completely fail to understand the technicalities of the above parameters and blindly agree to the manufactures spec sheet while buying an amplifier unit.The article explains a very straight forward circuit which can be easily built at home and used for determining the power of an amplifier output.
Here the proposed amplifier power meter circuit utilizes the magnificent IC LM3915 from TEXAS INSTRUMENTS, which takes the center stage and solely functions to convert the input from an amplifier to a direct LED readout, indicating the instantaneous power output levels.
How the Circuit Functions
The input to the IC is derived via a potential divider network R1/R2 built across the loudspeaker, connected to the amplifier.
The proposed design provides a maximum readout of 100 watts, however the circuit may be quickly modified for enabling higher readouts by adjusting the value of R2.
The LEDs begin sequencing in response to the varying power output from the speaker.
Through some careful inspection of the readouts, the average intermediate LED display may be identified and the respective marking of the LED may be noted as the RMS value of the amplifier, however that might be relevant to the particular set volume level.