Meters Circuits
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Recently, I have needed to measure inductances in the hundreds of microhenries to several millihenry range. Though I have a pretty good LRC meter and an excellent bridge on my workbench in Mesa, Arizona, I wanted to make these measurements in my home in.... -
Useful as a transmitter tune-up meter or an RF sniffer, this is an RF field strength indicator that is loosely based on the Broad Band RF Field Strength Probe, described elsewhere. It detects RF via a square law detector, basically its a crystal set with.... -
The circuit does not present particular difficulties for somebody that has a small experience. The two circuits are the himself, with a small difference only in their input, when they have they measure voltage or current and in connection that concern.... -
This is a successor of the PIC16C71 4-digit LED f-counter & V-meter. Some hard to find parts used in the previous version, which are out of production for some time, has been omitted. A rather early PIC16C71 has also been replaced by 28-pin device.... -
A bit-error-rate (BER) tester is a basic tool for digital-communications measurements. Although many commercial BER testers are available, you can easily design and build an inexpensive version. The scheme in Figure 1 has performance similar to that of a....
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This Field Strength Meter is simple and also quite sensitive. It uses an ordinary digital voltmeter to measure RF signal strength up to a few hundred MHz. The multimeter should be set to the lowest dc volts range for maximum sensitivity. This is normally.... -
This is a wide band signal strength meter circuit which responds to small changes in RF energy, designed to be used for the VHF spectrum and will respond to AM or FM modulation or just a plain carrier wave. This circuit measures radio field strength by.... -
Large moving-coil meters may require significant amounts of current for full-scale deflection, and using a shunt resistor may prove impractical when the meter current is larger than the current you are measuring. You can solve the problem by driving the....
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This is a simple rev-counter which can measure up to 100,000 rpm with method of strobe synchronization. Its usage is easy. Put a marker on the shaft before measureing, light on the shaft by flashing LED and adjust flashing frequency with the potentiometer as.... -
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Many beginners trying out their skill with QRP TX, for the first time have to overcome many problems before they are able to come on the air. On usual complaint is that, every thing is working fine but the signal is not going out. Here is a simple set up.... -
When I was recently debugging a design, I discovered that a short circuit existed from a ground plane to a power plane. I did not have access to a milliohmmeter or an equivalent tester for locating this type of short circuit. So, I logged onto the Internet....
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From a high-volume-production point of view of the Design Idea `Test batteries without a voltmeter` (EDN, Nov 9, 2000, pg 167), it is a time-consuming and laborious task to tweak the large number of potentiometers on each of the comparator input references.....
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This circuit is from Tomi Engdahl's page. It describes a nifty little TDR that, when combined with a regular oscilloscope, can be used to find discontinuities on long runs of cables... -
With a few inexpensive components and INT1Ch, you can turn the printer port of your PC into a high-current ammeter. This design`s goal is to make remote high-current measurements, but you can use this technique to remotely measure any other similar analog....
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VU (Volume Unit) meters used to be the mainstay of audio metering systems, but they have been replaced by LED metering in a great many mixers and other applications. Even in software, the most common level meter is made to look like an LED meter. The Peak.... -
The author's articles of months past focus on the application of 32-bit high-powered processors to amateur robotics and more recently applying CPLD technologies to the same. Continuing on this high-tech trend, this article will cover the concepts and....
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Using inexpensive components, you can fit a simple probe circuit into a pencil-sized enclosure. When both LEDs are on, the probe indicates the presence of an ac voltage; either LED alone indicates the presence and polarity of a dc voltage. The diode-bridge.... -
The spectrum analyzer circuit takes a stereo input and displays a volume by frequency display on a standard PC monitor. Finding the amplitude of a waveform at each frequency and then mapping this to the screen using a discrete number of levels achieve....
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This tiny pH-meter is very tiny: 11cm2 including the PSU circuit! I built it for the College Saint Pierre a few years ago. It is based on a circuit developped at the Facultes Notre-Dame de la Paix, Namur, Belgium. I modified several components to allow a.... -
Having found an u664b prescaler chip (Telefunken) from an old tv-tuner , I decided to build a valid frequency counter using pic16f84 , the prescaler I use is able to divide by 64 every frequency from 30 to 1300 MHZ. The original project is from Peter.... -
Ammeter is a great addition to any Laboratory Power Supply as it will measure the current consumption and help you determine if there are any problems with the circuit that you are building or testing. This amper meter is capable of measuring the current.... -
This circuit will give you a good, Accurate Watt Meter that can measure various power levels. In the Origional Article the Shunt was a .001 Ohm Copper Shunt giving a 1000 Watt Scale. However, because Most Circuit Breakers in homes are 15 Amps, I made my.... -
This circuit is designed to provide an inexpensive way to to create a High Impedance Voltmeter while making use of an inexpensive analog or digital multimeter. When measuring voltages in high resistance circuits the resistance of the voltmeter itself has an.... -
The Bray Barometer requires manual calibration for voltage offset and gain. Although practical on the workbench, these devices are most likely mounted in inconvenient locations making secondary adjustment difficult. The Bray Barometer uses potentiometers.... -
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Our CONTINUITY TESTER gives an audible indication of continuity between the probes so you can keep your eyes on the probe tip. Secondly its response-time is very short so that you can make lots of tests very quickly while listening for the beep. And.... -
This project is exactly what you need. It is simple to construct and can be connected to almost any analogue multimeter. The scales are accurate over each range - certainly good enough to provide you with the value of any capacitor between 1p and 10u. The.... -
Firstly, we will describe the "add-on" version for the 5x7 Display as this is the cheapest version and, quite frankly, it only deserves a few dollars as a piece of test equipment. It`s "all the rage" to have an Electrolytic Tester for servicing equipment.... -
This Field Strength Meter has been specially designed for our FM bugs. It is capable of detecting very low power transmitters and will assist enormously in peaking many of our FM transmitters that have a coil in the output stage that can be adjusted for.... -
This project has 3 features. 1. It`s a Field Strength Meter, 2. A Frequency Meter and, 3. An aid for testing detuned transmitters. Its uses will become clear in a moment but firstly let`s go over the background of a Field Strength Meter. A Field.... -
The LED power Meter 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....
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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