4 Differential Probe Manufacturers in 2022
This section provides overview, applications, and principles of differential probes. Also, please take a look at the list of 4 differential probe manufacturers and their company rankings.
Table of Contents
What Is a Differential Probe?
A differential probe is a device that detects noise generated from locations unrelated to the device transmitting the signal, such as ground vibration (called common noise), when measuring signals with oscilloscopes, etc., and amplifies the measurement signal with an amplifier to make it easier to measure.
In communications such as with USB and HDMI, it is necessary for the output side to detect signals accurately. Differential probe can be damaged or may not provide an accurate output if misused. In many cases, differential probe is available from the same company that sells oscilloscopes. Since they have excellent connectivity, it may be a good idea to purchase a differential probe from the same company as the oscilloscope.
Uses of Differential Probes
Differential probes are used in the prototyping and testing phases of many communication devices, such as USB, HDMI, DisplayPort, Ethernet, and SATA, to detect noise with an oscilloscope and determine if the noise is affecting the product. The differential probes are used to check if the noise does not affect the product and where the noise is affecting the product. Differential probes are often expensive, so it is important to properly investigate whether they meet the standards for use before purchasing.
Principle of Differential Probes
Differential probes consists of two active probes with exactly the same characteristics. One active probe is connected to the positive terminal of the connection of the device transmitting the signal to be measured, and the other to the negative terminal. By measuring the difference between the signals detected by these two probes, common noise can be detected.
Many differential probes are available with ingenious features that make it easier to measure waveforms with an oscilloscope. For example, low-voltage signals can be amplified by an amplifier to make them easier to measure with an oscilloscope, some voltages can be removed to the ground to avoid loading the oscilloscope with high-voltage signals, and signals can be made into clear square waves. If the differential probes are selected appropriately for the signal to be used, it is possible to measure a clear noise.
Equivalent Circuit of Differential Probes
Differential probes consist of two active probes, which are connected directly from the tip of the probe to the input end of a semiconductor circuit, so the input capacitance is extremely small, about 1pF.
On the other hand, unlike passive probes that use an attenuator, input resistance is in the tens of KΩ to 1MΩ range. Therefore, when differential probes are connected to a high-impedance circuit to measure waveforms, it is necessary to consider the measurement results in light of the influence of the probe.
In this case, connecting the equivalent circuit of the differential probes to the circuit under test and simulating the effect is an effective means.
In the case of differential probes, one pin and GND are connected in parallel with the input resistance and input capacitance published by the manufacturer. The other pin and GND are similarly connected in parallel with an input resistor and input capacitance.
Thus, between the two pins of the differential probes, the input resistance is doubled and the input capacitance is halved. Please judge the measurement results based on the effect of this impedance on the circuit under test.
High-Voltage Differential Probes
Differential probes are suitable for observing signal portions in a floating state, but common probes have withstand voltages of only about 30V to 100V for both differential and ground voltages.
Large high-voltage probes are required to measure floating points in circuits that handle high voltages, such as commercial power supplies. Probes with specifications of 6,000 V or more for differential voltage and 2,000 V or more for ground voltage are commercially available.
In measurements using high-voltage differential probes, the distance between the two pins must be sufficiently far apart to avoid the risk of electrical discharge. Inevitably, a cable is extended from each pin and connected to the measurement point.
As a result, ringing occurs in the high-frequency range due to the impedance of the lead wires, resulting in large amplitude fluctuations. As a countermeasure, twisting the two lead wires can suppress ringing.
High-voltage differential probes are also a very effective means of testing the operation of switching power supplies. In switching regulators, ground voltage can fluctuate by several hundred volts (common mode noise). Although the use of differential probes should cancel out the ground voltage fluctuations, it is inevitable that a small amount of the ground voltage fluctuation will actually be added to the differential output. To reduce the effect of this variation, select a probe with excellent CMRR (Common-Mode Rejection Ratio).
List of 4 Differential Probe Manufacturers
*Including some distributors, etc.
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Teledyne Technologies
Differential probe
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Differential Probe Manufacturer Ranking
*Including some distributors, etc.Number of Employees
Newly Established Company
- PinTech: 2006 (17 years ago)
- Pico Technology: 1991 (32 years ago)
- Chauvin Arnoux Metrix: 1905 (118 years ago)
Company with a History
- Chauvin Arnoux Metrix: 1905 (118 years ago)
- Pico Technology: 1991 (32 years ago)
- PinTech: 2006 (17 years ago)
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