The ground clamp meter / tester is an effective and time-saving tool when used correctly to make a measurement or place probes in the ground.

The clamp includes a transmit coil, which applies the voltage and a receive coil, which measures the current. The instrument applies a known voltage to a complete circuit, measures the resulting current flow and calculates the resistance (see figure 1).

The clamp method requires a to measure. The operator has no probes and therefore cannot set up the desired test circuit. The operator must be certain that earth is included in the return loop. The clamp tester measures the complete resistance of the path (loop) that the signal is taking. All elements of the loop are measured in series.

The method assumes that. Based on the math behind the method (to be reviewed below), the more returns, the smaller the contribution of extraneous elements to the reading and, therefore, the greater the accuracy.

In addition, it includes the bonding and overall connection resistance. Good grounding must be complemented by “”, having a continuous low-impedance path to ground. Fall of potential measures only the ground electrode, not the bonding (leads must be shifted to make a bonding test).

Because the clamp uses the grounding conductor as part of the return, will show up in the reading.

Unfortunately, the clamp ground tester is often misused . The clamp method is effective only in situations where there are multiple grounds in parallel. It cannot be used on .

Audio-Optical Isolation Amp
https://audioxpress.com/article/Audio-Optical-Isolation-Amp

This circuit enables the full galvanic isolation of sound frequency signals with optical transmission in excellent quality, eliminating interference.

When you connect audio components, interference may occur from various power and signal grounds.
For safety reasons, screenings are interconnected through the protection ground and the protection wire. The circuit that is formed this way opens a free path to the noise and hum from the power supply network and to the interference that originates from computers and other high-frequency generating equipment.
By eliminating protective grounds, you could reduce the problem, but this is not allowed, because all power equipment must have a protection ground. Disabling the already existing protection ground can be hazardous.

The ground loop problem can be overcome by galvanically isolating the video connections, for example at the aerial inputs of the surround-sound receiver and the TV.

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Posted Tuesday, April 23, 2013

These days many more audio-visual devices in the home are connected together. This is especially the case with the TV, which may be connected to a DVD player, a hard disk recorder, a surround-sound receiver and often a PC as well. This often creates a problem when earth loops are created in the shielding of the video cables, which may cause hum and other interference. The surround-sound receiver contains a tuner that takes its signal from a central aerial distribution system.

The TV is also connected to this and it’s highly likely that the PC has a TV-card, which again is connected to the same system. On top of this, there are many analogue connections between these devices, such as audio cables. The usual result of this is that there will be a hum in the audio installation, but in some cases you may also see interference on the TV screen.
The ground loop problem can be overcome by galvanically isolating the video connections, for example at the aerial inputs of the surround-sound receiver and the TV.
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Special adaptors or filters are sold for this purpose, known as video ground loop isolators. Good news: such a filter can also be easily made at home by yourself. There are two ways in which you can create galvanic isolation in a TV cable. The first is to use an isolating transformer with two separate windings. The other is to use two coupling capacitors in series with the cable. The latter method is easily the simplest to implement and generally works well enough in practice. The simplest way to produce such a ‘filter’ is as an in-line adapter, so you can just plug it onto either end of a TV aerial cable.

The only requirements are a male and female coax plug and two capacitors. The latter have to be suitable for high-frequency applications, such as ceramic or MKT types. It is furthermore advisable to choose types rated for high voltages (400 V), since the voltages across these capacitors can be higher than you might expect (A PC that isn’t connected to the mains Earth can have a voltage as high as 115 V (but at a very low, safe current), caused by the filter capacitors in its power supply.

These capacitors don’t need to be high value ones, since they only have to pass through frequencies above about 50 MHz. Values of 1 nF or 2.2 nF are therefore sufficient. To make the isolator you should connect one capacitor between the two earth connections of the coax plugs and the other between the two signal connections. The mechanical construction has to be sturdy enough such that the connections to the capacitors won’t break whenever the inline adapter is removed forcibly.

Sponsored by Digi-Key and Analog Devices: To prevent the propagation of dc and unwanted ac currents between input and output, while passing the desired signal, isolation is needed. Here are some ways to ease its integration into motor-control design.

The transition to Industry 4.0 has accelerated the adoption of robots, cobots (cooperative robots that interact with humans in a common workspace), and other advanced machines on the factory floor to generate higher levels of productivity. In addition, new energy standards are demanding ever-increasing levels of power efficiency.

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A bad cable installation destroyed my $2,000 TV and maybe almost killed me
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https://www.theverge.com/2016/5/18/11705038/cablevision-coax-destroyed-tv-nearly-killed-me