Vacuum Tubes Valves
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TV Video Circuits
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8051 / 8052
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H Bridge Circuit
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Meter Counter Circuits
Simple pH Meter Circuit A Low Cost Adapter for Your Digital Voltmeter
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..
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..
Voltmeter With LED For Car Battery
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 ..
DC RMS And Peak-to-Peak High Impedance Voltmeter
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..
Peak (Pulse) Voltmeter
This is a Peak Voltmeter circuit. This circuit can be viewed as a pulse stretcher, which catch fast pulse signal to be measured by a slow response voltmeter..
Build an Analog Bar Graph Expanded Scale Voltmeter
An expanded scale voltmeter (ESV) can save your plane. That may be a strong statement, but it`s true. The crucial radio link that lets you control your plane relies on nickel-cadmium (NiCd) batteries in the transmitter and receiver. If either of these batteries goes dead, you`ll lose control and your plane will likely crash or fly away. Unlike car
PEAK VOLTMETER FOR NARROW PULSES
Addition of dual-triode amplifier V2 to conventional peak voltmeter reduces charging time constant while increasing available time for measuring peak value. Linearity is good up to 40 v. -M. Uno, Amplifier Improves Peak Voltmeter Response, Electronics, 37:14, p 73.
Circuit generates low-frequency waveform whose amplitude is equivalent to that of unknown r-f voltage, using photochopper modulator VI-V2 as error detector. Arrangement gives seven voltage ranger from 10 my rms to 10 v rms full scale, over frequency range of 500 kc to 1, 000 Mc. -T. C. Anderson, Measuring Low-Level R-F Voltage with Servo...
PRECISION AC VOLTMETER
Measures a-c voltages between 95 and 135 v with 0. 6% accuracy while using ordinary 2% accuracy meter. Zener diodes provide reference voltage. -D. S. Belanger, Simple Circuit Increases Measurement Accuracy, Electronics, 38:22, p 69.
A wide-range voltmeter circuit. This inverting amplifier has a gain varying from -30 for the 10-mV full-scale range to -0. 003 for the 100-V full-scale range. Diodes D1 and D2 provide com-plete amplifier protection for input overvoltages as high as 500V on the 10-mV range, but if over-voltages of this magnitude are expected under continuous operati
This FETVM replaces the function of the VTVM while at the same time ridding the in-strument of the usual line cord. In addition, drift rates are far superior to vacuum tube circuits allowing a 0. 5 volt full scale range which is impractical with most vacuum tubes. The low-leakage, low-noise 2N4340 is an ideal device for this application.
BAR GRAPH VOLTMETER
This display uses ten LED`s to display a voltage range from 10. 5 to 15 volts. Each LED represents a 0. 5-volt step in voltage. The heart of the circuit is the LM-3914 dot/bar display driver. Trimmer potentiometer R5 is adjusted so that 7. 5 volts is applied to the top side of the divider. Resistor R7 and diodes D2 through D5 clamp the voltage...
CA081 and CA3140 BiMOS op amp offer minimal loading on the circuits being measured ‚The wide bandwidth and high slew rate of the CA081 allow the meter to operate up to 0. 5 MHz
A2N3819 FET provides a solid state VOM ‚The 2N3819 acts as a cathodefollowerin a VOM The biasoffset(meter null) is obtained with R14 and R12 sets full scale calibration R2 through R9 should totalabout10 M © R10 is a protective resistor and C2 provides ac bypassing to limit rf and noise pickup
SENSITIVE RF VOLTMETER
This schematic shows a peak-reading diode voltmeter driven by two stages of amplification. A 100- F capacitor provides a fairly large time constant, which results in satisfactory meter damping. The limited differential output voltage coupled with an overdamped meter prevents most needle pinning when you select an incorrect range position, or make
FET VOLTMETER 1
This FETVM replaces the function of the VTVM and rids the instrument of the usual line cord. In addition, FET drift rates are far superior to vacuum tube circuits, allowing a 0. 5 V full-scale range which is impractical with most vacuum tubes. The low leakage, low noise NPD8303 is ideal for this application.
WIDE RANGE AC VOLTMETER
In this circuit, a diode bridge is used as a meter rectifier. The offset voltage is compensated for by the op amp, since the bridge is in the feedback network.
SINGLE CHIP DIGITAL VOLTMETER
This 4 1/2-digit DVM circuit is built around a Maxim ICL7129ACPL A/D converter and LCD driver. An ICL8069 CCZR 1. 2-V band-gap reference diode is used for a voltage reference. S2a-b-c select one of four ranges up to 200 V (maximum). The meter also has a piezoelectric buzzer for continuity testing. S3 selects either DVM or continuity. Crystal 1 can
BAR GRAPH READOUT VOLTMETER
Sections of RS339 quad comparator each drive LED to give indications of four different input voltage levels, While LED 1 is connected to ground for use as zero indicator Resistors shown are for Radio Shack 276-041 red LEDs ›change R6-R9 to 270 ohms and R1 to 470 ohms for green LEDs Pot R1 is used to calibrate voltage divider R2-R5 With R1 set all
Fundamentals of Electrical Engineering and High-impedance voltmeter
Vacuum-tube or electronic voltmeters make use of some of the unique characteristics of electron tubes, and so are available in many types. They are available for measuring direct, rms, average or peak voltages. Of the many types available, only the simplest and possibly the most commonly used type for measuring rms values of alternating voltages...
In the voltage to time conversion section, the analog input voltage is fed to the attenuation circuit. The attenuated signal is compared with the the ramp signal generated by the ramp generator given in the block diagram by the input comparator `C1`. Similarly, The ramp signal generated is compared with 0V via a zero-crossing detector `C2`. A...
Linear AC voltmeter circuit diagram
The use of diode rectifiers in AC voltmeters with a low lower limit of measurement range (0. 5. 1 V) leads to significant nonlinearity of the scale because of the nonlinearity of current-voltage characteristics of diodes. The use of electronic amplifiers in rectifier circuits allowing to linearize the scale but requires a power supply. At the...
VOLTMETER WITH IMPROVED LINEARITY CIRCUIT DIAGRAM
The device uses a microammeter with full scale deflection of 50 uA and with the resistance of 2 kilohms. The upper limit of the measuring range of the voltmeter is 1 V, and in the range of 0. 2. 1 V the measurement error due to the nonlinearity of the scale is less than 1% of the full scale range. By selection of the resistor R3 values the...
Frequency Meter Circuits
VU Meter Circuits
Ultrasonic distance finder circuit
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 measured. There are three main categories of distance measurement methods in use: a) By...
Simple Metal detector circuit with CD4030
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 find something potentially valuable, hidden a few centimeters below the soil. So many...
Fully automatic watering circuit for flower pots
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 circuit comes as a solution to this problem. Depending on humidity of the pot at...
Simple deep searching metal detector circuit
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 circuit of this metal detector, it is possible to detect a metal coin in depth of 90 to...
Sub-Harmonic Bass Converter for Electric Guitars
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, such as filtering or distortion. Instead, a frequency division system produces outputs...
Echo Depth Sounding Sonar for Boats
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 calibration of the rope. This arrangement still exists in some yachts. The big...
100W HiFi Audio Amplifier Circuit
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 supply must be symmetrical so that no electrolytic capacitors are needed at the outlet....
Plant-Pot Water Level Indicator Circuit
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. The circuit of the device is shown in Figure 2. The water detection is made from the bottom...
Analogue Sound Preasure dB-Meter Circuit
The best human ear can capture sounds from 20Hz to 20KHz. These limits are known to be the broadest that can exist. Normally the normal limits range from 100Hz to about 13KHz and depend on the age and health of the individual. We for our measurements and to have a good accuracy we will get the limits of 20Hz to 20KHz. A sound to be heard does...
DIY HV Variable Capacitor
DIY PMA Alternator Plans
Digital Signal Integrity