DS

A milli Amp analog meter often used along with audio system can be easily converted into a decent volt meter, all that is needed is an understanding of the requirement and the meter. In case a 10V full scale meter is to be designed, then a 10K resistance is to be put in series with the meter coil so that for an applied voltage of 10V a meter can receive 1milliAmp only. The meter itself has an internal resistance and if that is measured properly then in actual practice the resistor to be connected in series shall be having a value of 1000 ohms – IR (internal resistance of the meter). When we measure smaller voltage then this internal resistance of the meter plays a significant role, say for this particular case the internal resistance is 86 ohms, hence, for a I.V. full scale meter the value of the external resistance would be (1000-86) 914 ohms. The milli amp meter can also be used as an Amp meter of higher currents by adding shunt resistances. This is being achieved by simple net...

‘Hello… HELLO! Are you deaf? Do you have disco ears?’ If people ask you this and you’re still well below 80 , you may be suffering from hearing loss, which can come from (prolonged) listening to very loud music. You won’t notice how bad it is until it’s too late, and after that you won’t be able to hear your favorite music the way it really is – so an expensive sound system is no longer a sound investment. To avoid all this, use the i-trixx sound meter to save your ears (and your neighbor's ears!). With just a handful of components, you can build a simple but effective sound level meter for your sound system. This sort of circuit is also called a VU meter. The abbreviation ‘VU’ stands for ‘volume unit’, which is used to express the average value of a music signal over a short time. The VU meter described here is what is called a ‘passive’ type. This means it does not need a separate power supply, since the power is provided by the input signal. This makes it easy to use: just conne...

This is 5V drive IC WS2801 magic RGB Dream Color Series Programmable LED Flexible Strip Lights, 32LEDs per meter, 160LEDs per reel, Full color LED strip light, Digital led flexible strip, Can perform various effects by full color led controller. The WS2801 IC now only has 4 pins, durable and easy for installation. This simpler layout and can be controlled separately to each one lamp, every LED is cuttable. Low working voltage, DC5v, ensure safety in wet condition. The transparent of silicon glue and epoxy resin glue can make the light transmittance reach at least 90%,the bare board can make it up to 100%. our company specialize in designing drive control scheme and developing new product  for led decorative lighting and LED lighting industry, providing all-dimensional solutions.We mainly engaged in designing and selling the led lighting drive IC,LED lighting constant current driving IC,LED lighting control system. Good service,comprehensive pre-sale and after-sale service, also pro...

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. This circuit can also be integrated into audio amp projects.  Circuit Schematic Part Total Qty. Description Substitutions C1 1 2.2uF 25V Electrolytic Capacitor C2, C3 1 0.1uF Ceramic Disc Capacitor R1, R3 2 1K 1/4W Resistor R2 1 10K 1/4W Resistor R4 1 100K 1/4W Resistor R5 1 1M 1/4W Resistor D1 1 1N914 Silicon Diode Q1 1 2N3906 PNP Transistor LED1-LED10 10 Standard LED or LED Array U1 1 LM3915 Audio Level IC MISC 1 Board, Wire, Socket For U1 Notes V+ can be anywhere from 3V to 20V. The input is designed for standard audio line voltage (1V P-P) and has a maximum input voltage of 1.3V. Pin 9 can be disconnected from +V to make the circuit use a moving dot display instead of a bar graph display. Thanks to help from the forum, this circuit has ...

Also suitable for Headphones Operates in conjunction with a DVM A simple Impedance Meter can be useful to measure the actual impedance a loudspeaker or headphone is presenting @ 1kHz standard frequency. The circuit, designed on request, relies on an earlier design (Spot-frequency Sine wave Generator) to obtain a stable, low distortion 1kHz sine wave avoiding the use of thermistors, bulbs or any special amplitude-limiting device. The sine wave output, after some amplitude setting obtained by means of P1, is sent to the device under measurement through a resistor. A regulated supply is necessary to obtain a stable output waveform. D1 and D2 force IC1 to deliver 6.2V output instead of the nominal 5V. The measurement is done in two stages: as a constant current supply of the device under test is necessary, this can be set at first by adjusting P1 and measured across the series resistor (R7 or R8, depending on the impedance value to be measured); then, the meter is switched across the dev...

Errors and their Adjustments in 1Φ energy meter Energy meters should give correct readings over a period of several years under normal use conditions. Some of the common errors in energy meter and their remedial measures are discussed below. 1.        Phase Error: It is necessary that the energy meter should give correct reading on all power factors, which is only possible when the field setup by shunt magnet lags behind the applied voltage by 90 o . But the flux due to shunt magnet does not lag behind the applied voltage exactly by 90 o because of winding resistance and iron losses. Adjustment: The flux in the shunt magnet can be made to lag behind the supply voltage by exactly 90 o by adjusting the position of shading band (or shading ring or shading coil) placed round the lower part of the control limb of the shunt magnet. This adjustment is known as lag adjustment or power factor adjustment (or power factor compensator ). 2.     ...

This is a Simple LED Volt meter to Monitor the charge level in Lead Acid Battery or Tubular battery. The terminal voltage of the battery is indicated through a four level LED indicators. The nominal terminal voltage of a Lead Acid battery is 13.8 volts and that of a Tubular battery is 14.8 volts when fully charged.  Simple LED Volt Meter Circuit Diagram The LED voltmeter uses four Zener diodes to light the LEDs at the precise breakdown voltage of the Zener diodes. Usually the Zener diode requires 1.6 volts in excess than its prescribed value to reach the breakdown threshold level. When the battery holds 13.6 volts or more, all the Zener breakdown and all LEDs light up. When the battery is discharged below 10.6 volts, all the LEDs remain dark. So depending on the terminal voltage of the battery, LEDs light up one by one or turns off.

The circuit below uses two quad voltage comparators (LM339) to illuminate a series of 8 LEDs indicating volume level. Each of the 8 comparators is biased at increasing voltages set by the voltage divider so that the lower right LED comes on first when the input is about 400 millivolts or about 22 milliwatts peak in an 8 ohm system. Circuit diagram : 8 Stage LED VU Meter Circuit Diagram The divider voltages are set so that each LED represents about twice the power level as the one before so the scale extends from 22 milliwatts to about 2.5 watts when all LEDs are lit. The sensitivity can be decreased with the input control to read higher levels. I have not built or tested this circuit, so please let me know if you have problems getting it working. The power levels should be as follows: 1 LED = 22mW 2 LEDs = 42mW 3 LEDs = 90mW 4 LEDs = 175mW 5 LEDs = 320mW 6 LEDs = 650mW 7 LEDs = 1.2 Watts 8 LEDs = 2.5 watts

This is an audio power meter simple with this circuit , dual LED starts to light green around 0.1 watts into 8 ohms ( 0.2 watt into 4 ohms ). Naturally, this depends on the specific type of LED is used. Despite being a simple equipment he is impressively bench since with a load resistor connected to output of speakers is possible to measure the sound level up , or just check its output . Audio Power Meter Circuit Diagram

As electrolytic capacitors age, their internal resistance, also known as "equivalent series resistance" (ESR), gradually increases. This can eventually lead to equipment failure. Using this design, you can measure the ESR of suspect capacitors as well as other small resistances. Basically, the circuit generates a low-voltage 100kHz test signal, which is applied to the capacitor via a pair of probes. An op amp then amplifies the voltage dropped across the capacitor’s series resistance and this can be displayed on a standard multimeter. In more detail, inverter IC1d is configured as a 200kHz oscillator. Its output drives a 4027 J-K flipflop, which divides the oscillator signal in half to ensure an equal mark/space ratio. Two elements of a 4066 quad bilateral switch (IC3c & IC3d) are alternately switched on by the complementary outputs of the J-K flipflop. One switch input (pin 11) is connected to +5V, whereas the other (pin 8) is connected to -5V. The outputs (pins 9 & ...

Here are very simple project of Sound VU Meter Circuit Diagram. This circuit is a sound level meter, very simple, but very effective for your sound system or test bench. This type of circuit is also called a VU meter. 'Abbreviation means "unit volume" is used to express that the average value of a music signal over a short period of time. Sound VU Meter Circuit Diagram The VU meter described here is what is called a type "passive". This means that does not require a separate power source, since the power is supplied by an input signal. This makes it easier to use:. Just connect it to the speaker terminals (polarity does not matter) and is ready to use.

LED power Meter circuit is a simple RF detector using diodes to charge a capacitor. The voltage developed across the capacitor is indicated by a multimeter set to a low voltage range. The circuit is soldered together without the need for a PC board , as can be seen in the diagram below and paper clips are used for the positive and negative terminals of the multimeter. The level power output of an FM transmitter is indicated by the illumination of a LED and the voltage reading on the multimeter gives a further indication of the output. A digital multimeter may be used but the presence of RF may produce a false reading. Likewise, the radiated energy may upset some analogue meters and you may get full scale deflection on the 15v range as well as the 250v range! But the LED won't lie. It will accurately indicate the RF and you can see the change in brightness as you adjust the coils in the output stage. Some of the cheapest and simplest multimeters will give the best results as...

Description  In the circuit below, a quad voltage comparator (LM339) is used as a simple bar graph meter to indicate the charge condition of a 12 volt, lead acid battery. A 5 volt reference voltage is connected to each of the (+) inputs of the four comparators and the (-) inputs are connected to successive points along a voltage divider. The LEDs will illuminate when the voltage at the negative (-) input exceeds the reference voltage. Calibration can be done by adjusting the 2K potentiometer so that all four LEDs illuminate when the battery voltage is 12.7 volts, indicating full charge with no load on the battery. At 11.7 volts, the LEDs should be off indicating a dead battery. Each LED represents an approximate 25% change in charge condition or 300 millivolts, so that 3 LEDs indicate 75%, 2 LEDs indicate 50%, etc. The actual voltages will depend on temperature conditions and battery type, wet cell, gel cell etc. Circuit Diagram  Source - http://www.bowdenshobbycircuits.info/...

This circuit is used to measure the current from a solar panel. It has very low power loss for currents in the 0-10A range. It also works as a general purpose DC current meter. The circuit can be used on either the positive or negative side of a DC circuit. Specifications Measured Current: 0-10 Amps DC Circuit Voltage: Will work with DC circuits at any practical voltage. Accuracy: approximately 2%, depending on the meter movement. Theory The current to be measured flows through the 0.01 ohm resistor which causes a small voltage drop across the resistor. The 100 microamp meter is set up with the series 50 ohm and 500 ohm variable resistor in a voltage measurement configuration to measure this voltage drop. The 500 ohm variable resistor is used to adjust the meter's full scale reading. The 50 ohm resistor limits the maximum current to the meter no matter what setting is on the 500 ohm resistor, this protects the meter from passing too much current and burning up. The series resistanc...

Simple phase shift measurement can be done by squaring both the measured and the reference, then compute the difference of the two signals. The accuracy of the circuit shown in the schematic d iagram  below is 1% UP to 2000 cps. This circuit is used in computers and for high speed analog instrumentation. Negative value for zero phase shift is indicated by the zero center DC ammeter, zero for 90′ phase shift and some maximum value for 180′ phase shift.  Phase-Shift Meter for Audio Frequency Signal Circuit Diagram

Here is a simple Electronic Circuit Project of VU Meter 1 with transistor Circuit. This is Simple Circuit of optical index of level of sound signals, adapted in various needs of user. It can be adapted in various levels of entry, regulated from trimmer TR1 (Level) - TR2 (Gain), then it is rectified by the D1-2 (cutting off of negative periods of signal-rectification) and drived to the main circuit of index, that it is constituted by D3...D13 , the transistors Q2-Q13 and the materials that exist around them.  VU Meter 1 Using with Transistor Circuit Diagram: The optical index him we take from the line of LED LD1-13. The each led turns on when the level is altered at 0,65V roughly. The requirements in current are 100 ma with complete index. We can add all units LED we want, always calculating the current where they will need the news LED. Parts List of  VU Meter 1 Using with Transistor :