VU Meters

The circuit was designed to work with an audio power amplifier which operated off +18v-0v-18v power rails. The actual voltage used is not too critical except that the feedback is referred to the LED chain which itself is anchored to a +12v rail, hence the separate stabilizer for this. It has one large advantage over most of the LED chips available - all the LEDs are in series so it only draws 20mA irrespective of the number of LEDs illuminated. The two input op-amps form a rectifier circuit to rectify the audio input level. The changeover switch converts the circuit from average reading to peak reading...

Analogue VU meter

Analogue VU meter

This circuit can drive analog moving coil meters, for use as a VU meter. The circuit is left connected to the line terminals of the amplifier. The VU meter works pretty simple. T1 and T2 signal increase. The signal is then rectified by two diodes and fed to the meter. The capacitors C3 and C4 ensure that the voltage is slightly flattened and the meter responds less quickly. After building the circuit must be calibrated. End, the VU meter connected to a tone generator that delivers 0.3 V at 1000 Hz. Then P1 is fully opened, ie the bishop of P1 located at the entrance. Then P2 regulates off so that the full deflection meter. P1 is then adjusted so that meter 0.5 mA (= half results) indicates. For a stereo VU meter circuit should be built twice...

10 LED VU meter LM3915

10 LED VU meter LM3915

This simple LED VU meter has only a few parts but is useful as an indicator for the noise. The circuit is built around an LM3915, the brother of the logarithmic LM3914. The input signal from the VU meter is put on pin 5 of IC1. Through pin 9 of IC1 is the display mode sets (beam or point instructions). In the drawn state IC1 works in the dot mode (point). When pin 9 is coupled to pin 3, the IC works in bar mode (beam). Obviously the whole circuit consumes less power in dot mode...

LED audio peak level

LED audio peak level

A peak level indicator when a signal exceeds a certain maximum value. It can be quite useful, for instance, with tape recorders, mixing consoles etc. One of the most important requirements of a peak level indicator is that it should respond to very short signals. The circuit is built using a CMOS inverting Schmitt trigger type 74C14. The input impedance of the peak indicator is fairly high. The value depends to some extent on the position of TR1. The unit functions as follows. The input is half- wave rectified by D1. When the voltage across R1 exceeds the upper trigger threshold, a logic [H] is produced at the output of the second Schmitt trigger. ..

20 LED VU meter

20 LED VU meter

A circuit of measurement of level based on a typical application of National. The circuit round the IC1 makes input adaptation and amplification with the trimmer TR1 [GAIN]. The circuit round the IC2 makes half-wave rectification of acoustic signal. With switch S1, we select the type of indication, that we will have from the LED. With the prices in resistances R6 and R7 that exists in the circuit, the level of signal, in the entry is 7.8V (gain of first stage IC1, is one), and the difference of level between the LED D10-11, should are 3 db. The positive department of supply, should have the possibility of giving more current, one and it is overloaded with the current of LED.. ..

VU meter circuit

VU meter circuit

The circuit is placed parallel with the exit of power amplifier and us gives the level of signal ,from output. Changing resistance R1, in the input circuit, we adapt the indication of power, in the resistance of loudspeaker, that we use. ..

VU Meter with UAA180

VU Meter with UAA180

This circuit of measurement of level uses the UAA180 of SIEMENS and a circuit of rectification of precision, round the IC2B. The calibration has become in steps 3db from the one Led in the other, ensuring, a very good rate of precision, in the measurement of entering acoustic signals. The Led can be square, thus when they are placed the one by in the other, they give the picture of bar, without space. ..

Vu Meter For Amplifiers

Vu Meter For Amplifiers

One yet circuit with the known LM3915. It does not differ in a lot of points from other applications with same IC. The circuit accosted in those who they want a Vumeter that will be connected in the exit of power amplifier. It can be adapted his sensitivity so as to it works with amplifiers that have different out power, enough we change the R1 price of according to Table 1. The price that will be found if it does not correspond in standard resistance price, it should selected the next standard price or if you want the biggest precision it should you put resistances in series or parallel so that you achieve the price. Can use various types Leds round or square, so that you take the optical and aesthetic result that you want. With switch S1 selects if the Vumeter works as bar or dot. ..

30 LED audio frequency analyzer

30 LED audio frequency analyzer

This analyst is, a sensitive instrument, in the frequency changes and width of a acoustic signal. Thus the brightness of LED that turns on each moment of is proportional signal width, while the colour of proportionally frequency. The circuit input sensitivity is regulated with R2, in order that in powerful signals they turn on the red LED, in the middle the yellow LED and in the low green LED. The display unit, is constituted by 3 lines of 10 LED the every, what is checked by a counter decoder (IC2). Two gates IC?-b, function as the IC2, with the R6 regulate the frequency. When does not exist signal in the input, then no one LED does not turn on. As soon as it will be applied signal, then the LED will begin to blink depending on the rythm and the intensity of signal...

10 LED VU meter with LM3915

10 LED VU meter with LM3915

Supply voltage: 12 V. Supply current: 10 mA in stand-by, max. 80 mA. Input voltage: min. 20 mV rms. Indication range: 30 dB. LED currents: 7 mA. Ref. voltage of IC2: 5 V..

9 LED VU meter

9 LED VU meter

This simple and easy to make circuit is a 5 LED VU Meter based on LB1409 IC from SANYO, which will indicates the volume level of the audio signal it senses. SUPPLY 12V DC @ 50mA. PR1 REF SET. PR2 AUDIO LEVEL SET..

DB level meter with LM3915

DB level meter with LM3915

This project uses an LM3915 bar-graph IC driving two sets of ten LEDs for a 30dB range. The circuit is unique because it has an additional range of 20dB provided by an automatic gain control to allow it to be very sensitive to low sound levels but it increases its range 20dB for loud sounds. The LEDs are operating at 26mA each with the brightness control at maximum, which is very bright. The circuit has a switch to select the modes of operation: a moving dot of light, or a bar with a changing length. It has a little 9V Ni-Cad rechargeable battery in it to be portable and the battery is trickle-charged when the project is powered by a 9V AC-DC adapter...

VU meter with LM3915

VU meter with LM3915

This nifty sound level meter is a perfect one chip replacement for the standard analog meters. It is completely solid state and will never wear out. The whole circuit is based on the LM3915 audio level IC and uses only a few external components...

VU Meter with Audio Mixer circuit

VU Meter with Audio Mixer circuit

This is audio mixer circuit. The circuit is for one channel input, if you need, for example 5 channel mixer, then you need to build 5 similar circuits...

LED VU Meter with LM3914N

LED VU Meter with LM3914N

The circuit is based on an LM3914N bar graph display driver device (IC1), which can be used to drive up to ten LEDs. This is connected so that with OV12 at the input only the first LED indicator switches on. This simple peak reading VU meter circuit uses six LEDs to indicate six signal levels at 14, 8, 3, 0, +3, and +6dB, or any other levels having the same spacing (e.g. 17, 11, 6, 3, 0, and +3dB, if preferred). About 24mV peak to peak is needed in order to activate the highest LED indicator, so the circuit is sufficiently sensitive to be used with any normal item of audio equipment...