Meters Circuits
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The circuit shown is a simple digital frequency meter, which indicates the frequency in hertz of an astable 555 timer. It could, perhaps, be adapted for other uses. An NPN transistor, TR2, is connected to the 555 astable to be measured, as shown in the....
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This 1-kHz linear-scale analog frequency meter circuit uses the 555 as a pulse counter. Frequency is read on M1, (or 1 mA meter) which can be calibrated to read 0 to 1 kHz....
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The circuit can measure the frequency between 1. 5kHz ~ 500kHz by connecting C1 ~ C6 different capacitors. The maximum frequency is up to 1MHz. Transistor T1 can be used as the integrator, and its load resistor is 15k © resistor and R1 ~~ R6 adjustable....
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The proximity detector senses the passing of the PC board pieces as the wheel rotates, providing an output signal, which has a clean transition between high and low voltage levels, and is ideal for triggering counting or processing circuits. Next is the....
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A basic digital voltmeter circuit using the Harris Semiconductor ICL7107 is shown. It has a 2-V range. Calibration consists of applying a known voltage of 1.2 V to the input and adjusting R3 for a correct reading on the display. Supply is ±5 V, and S1....
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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....
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This figure shows the schematic diagram of the simple inductance meter. U1, a 74LS00 two-input quad NAND gate logic integrated circuit, two resistors, a capacitor, and a surplus microprocessor crystal form a stable crystal oscillator near the marked....
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Switching of feedback resistors for opamp driven by Radio Shack 276-115 selenium solar cell gives multirange linear light meter. With 1000-megohm resistor for highest sensitivity, star Sirius will produce pho-tocurrent of about 25 pA when aolar cell is....
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The thermistor RT and R1, R2, R3 and RP1 form a temperature measurement bridge. When temperature is at 20 ?, using R1, R3 and adjusting RP1 can allow bridge to keep balance. When temperature rises, the resistance of the thermistor RT reduces, the bridge in....
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Using an LM3915 VU meter LED bar graph driver?10 LEDs are driven?A simple audio amplifierdrives a detector circuit?which provides dc drive for the LM3915....
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The input stage of this voltmeter circuit uses operational amplifier and diode feedback to form linearity peak value rectifier circuit. Through R2/R2 partial pressure isolation, it is sent to double multi-channel BCD output A/D converter CA3162E, it also can....
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This circuit shows an ICM7217 and an ICM7555 that are connected as a basic frequency counter. The connections between the ICM7217 and a common-cathode LED display are shown in Fig. 12-18. The frequency counter is calibrated (against a known standard) using....
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Here is to introduce the LED car voltmeter which is made of the op-amp LM312 and LED, it can display 6 gears of voltages, 10-15V, each gear is 1V. The working principle of the circuit The LED car voltmeter consists of the regulator circuit, Vref circuit,....
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The LED car voltmeter consists of the filter circuit, voltage distribution filter circuit, voltage amplifier circuit and LED display circuit, see as figure 7-77. The regulator filter circuit consists of the 3-terminal IC1 and filter capacitor C1. The voltage....
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This is the electric thermometer circuit composed of LM134. In the circuit, the voltage or current output by LM134 is in proportion to the thermodynamics temperature, which can be read out on the 100?A meter, the test temperature range of the meter is....
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When this thermometer is used in the room, it can work in the intermittent way, and this working state can be kept in the temperature test circuit, because internal temperature doesn`t change sharply. The astable multi-resonance oscillator consists of VT1....
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The resolution of the barometric pressure is about 0. 00417 inHg (0. 0139 kPa) for a pressure range of 31. 0 to 28. 0 inHg (105. 0 to 95. 0 kPa, or 1050 to 950 mb or hPa). Better resolutions are possible with a more restricted pressure range. The circuit....
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Capacitance meter is one instrument that you should have in your toolbox if you are an electronics hobbyist, or if you`re a professional electronic technician....
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Measuring inductance is important in making your hand-made inductors, especially when you do-it-yourself (DIY) your coil winding. An inductance meter adapter....
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What is A pH Meter? A pH meter is actually a precise voltmeter that measures the generated voltage of a pH electrodes. The requirement of such meter is high....
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Inverting mode amplifier is needed by precision accelerometers because that usually charge output device. This amplifier is used to convert charge into voltage....
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This is a simple temperature measurement probe circuit. This circuit measures temperature either on a PC board or at the probe tip to which contains the....
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This is a circuit of FETVM-FET Volmeter. The function of the VTVM is replaced by the FTEVM while at the same time ridding the usual line cord instrument. This....
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LM135/235/335 temperature sensor is designed ease absolute temperature reading, giving all positive value for any frequency, that`s why we read 2.7315V at 0....
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Pulses are received by the timer from the distributor points. When the timer output is high, Meter M receives a calibrated current through R6. The meter don`t....
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Below is a comparator circuit which is can measure with step of 1 volt, the voltage of car battery. The indication of voltage is done by comparison of ....
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Analog meter normally doesn`t have high impedance since they don`t have buffer circuit inside. With active buffering, the input impedance of this circuit....