LED Audio level meter

lam power levels as well. The IC contains an adjustable voltage reference and an accurate ten-step voltage divider. The input buffer drives 10 individual com- parators referenced to the precision divider. The power indication at the changeover points (the level at which a particular LED will light) of each indi- vidual LED is shown in the circuit diagram. The input signal to the circuit is taken directly from the output of the power amplifier, that is, in parallel 23 LED audio level meter A feature of contemPory power amplifiers is an out- put power level indication consisting of a row of LEDs rather than a mechanic& meter. The number of LEDs illuminated in this type of display corre- sponds to the output level of the amplifier. A "bar meter" of this type can be added to any power am- plifier with the aid of the circuit shown here. The heart of the circuit consists of the LM 3819 ICa from National Semiconductors which produces 100W 50W 25W 13W 6W 3" logarithmic scale and can there...