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.... -
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.... -
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.... -
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.... -
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.... -
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.... -
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.... -
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.... -
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.... -
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.... -
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.... -
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.... -
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,.... -
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.... -
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.... -
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.... -
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.... -
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.... -
Measuring inductance is important in making your hand-made inductors, especially when you do-it-yourself (DIY) your coil winding. An inductance meter adapter.... -
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.... -
Inverting mode amplifier is needed by precision accelerometers because that usually charge output device. This amplifier is used to convert charge into voltage.... -
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.... -
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.... -
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.... -
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.... -
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 .... -
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....
New Circuits
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This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of.... -
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is.... -
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to.... -
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This.... -
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the.... -
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,.... -
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the.... -
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power.... -
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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