In contrast to an ordinary voltmeter, the input of an oscilloscope generally has one side (GND) connected to ground via the mains lead. In certain situations this can be very problematic. When the measuring probe is connected to a circuit that is also connected to ground, there is a chance that a short is introduced in the circuit. That the circui
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t, and hence the measurement, is affected by this is the least of your problems. If you were taking measurements from high current or high voltage (valve equipment) circuits, the out-come could be extremely dangerous! Fortunately it is not too difficult to get round this problem. All you have to do is make the input to the oscilloscope float with respect to ground. The instrumentation amplifier shown here does that, and functions as an attenuator as well. The AD621 from Analog Devices amplifies the input by a factor of 10, and a switch at the input gives a choice of 3 ranges. A GND` position has also been included, to calibrate the zero setting of the oscilloscope. The maximum input voltage at any setting may never exceed 600 VAC. Make sure that R1 and R8 have a working voltage of at least 600 V. You could use two equal resistors connected in series for these, since 300 V types are more easily obtainable. You should also make sure that all resistors have a tolerance of 1% or better. Other specifications for the AD621 are: with an amplification of 10 times the CMRR is 110 dB and the bandwidth is 800 kHz. If you can`t find the AD621 locally, the AD620 is a good alternative. However, the bandwidth is then limited to about 120 kHz. The circuit can be housed inside a metal case with a mains supply, but also works perfectly well when powered from two 9V batteries. The current consumption is only a few milliamps. You could also...
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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