Questions tagged [probe]

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1answer
51 views

Replacement 100 ohm resistor for differential scope probe? [closed]

I'm trying to use a P7504 ($$$) "TriMode" scope probe, and unfortunately the resistors eventually break. Does anyone have recommendations for a 100ohm resistor that would replace the ones on the probe?...
1
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3answers
81 views

What probe/tip to use to clip into a PCB test point?

I need to have a digital logic analyser connected to a test point of a PCB board I'm developing for. To be clear, I mean the little ~0.5mm hole kind of test points. What kind of probe would allow me ...
2
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1answer
99 views

10:1 transformer 10X oscilloscope probe

Why are transformer based oscilloscope probes not common? It should be possible to put a miniature 10:1 signal transformer at the probe tip, and connect it straight to the 50ohm input of the ...
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1answer
102 views

Current Probe with 1mA precision [closed]

I've designed this circuit for a 1 mili amp precision current probe, what change should I apply to it?
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2answers
66 views

How to make sense of the signal trace of differential signal

I am trying to understand following signal trace picture that is shown on the wiki page of 1553 Bus. The Bus has balanced differential pair wires. As the 1553 bus has differential signals on the ...
1
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1answer
83 views

Can't get Flyswatter2 probe to work with OpenOCD

I've got a Flyswatter2 flash/debug probe from the company Tin Can Tools (see https://www.tincantools.com/product/flyswatter2). Unfortunately, I can't get it to work with OpenOCD. Below is a detailed ...
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2answers
70 views

Length to make magnetic loop antenna/probe for 1.6GHz?

I'm making a near-field probe to to search for GNSS (GLONASS) blocking signals on my PCB. According to http://www.eryptick.net/unisold/loop.html the wire length for a loop should be 1/3 the ...
0
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1answer
44 views

Current probe settings and measurement

I am having this Current probe I am using this to measure the inductor peak current. Inductor is rated at 2.05A. Schematics : Input Voltage to the converter during measurement is 7.5V I am ...
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2answers
1k views

How this DIY High-Speed Probe doesn't reflect signals?

I am reading The Art of Electronics, page 809 and 810, where they show this probe: Which is a DIY probe, made out of a RG-178 coaxial cable, in series with a 953 ohms resistor. I wonder why the 953 ...
1
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1answer
52 views

How can I implement a differential input for a logic analyzer probe?

I'm currently working on a project to build a portable logic analyzer. There will be 4 input channels to the design, however I was highly recommended to redesign this using a differential input to ...
2
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3answers
76 views

Maximum Input voltage of the DSO shell oscilloscope and TL084

In jyetech forum FAQ they mentioned that DSO shell is capable of measuring up to 50V directly: DSO Shell was designed for low voltage measurement. The maximum input voltage was specified as 50Vpk ...
0
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1answer
162 views

How to update the SWDAP firmware?

1. About the SWDAP probe I bought an SWDAP probe some time ago from L-Tek (see https://www.l-tek.com/web-shop/l-tek-swdap-interface/). It took me some time to figure out the terminology, but I ...
11
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2answers
1k views

Is it acceptable to use decoupling capacitor ground pad as ground for oscilloscope probe?

If one were to probe with an oscilloscope using the short ground spring clip attachment, and use the ground pad of a decoupling capacitor as the ground, would the measurement be thrown off at all by ...
1
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1answer
34 views

Finding out the accuracy of the current probe's measurement

As part of power supply testing we are measuring the current profiles of various regulators. Startup profiles includes current bursts with different current amplitudes and widths. i want to ...
4
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2answers
188 views

Criticism of my differential pH probe design

I finished and tested with buffers this little differential pH probe on a perfboard, it works, 3 points calibration is linear. The ground electrode is a stainless steel rod wired to the GND of the ...
3
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1answer
51 views

To find theRMS noise voltage in a circuit, can the measured RMS voltage be subtracted from the RMS voltage of shorted probes?

I'm trying to estimate the SNR of a circuit, which includes measuring the noise power of an analog trace. Right now, I'm attempting to measure the noise with a high bandwidth scope probe, ac coupled, ...
0
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1answer
24 views

Probe max voltage (50:1)

I'm preforming some measurements with a differential probe and I'm not sure what is the correct attenuation ratio I should use (measuring about 300 V voltage drop on a varistor, which is a surge ...
2
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1answer
71 views

Why do we ground the common probe on a 3 probe liquid level sensor?

I have a liquid level sensor with 3 probes, one us common, the other is for low level and the third is for high level. On the liquid level control relay diagram, I've noticed that the common probe ...
0
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0answers
117 views

Test LVDS signals

I am wondering how I could test LVDS signals on a PCB using a scope. The most straight forward answer would be to measure on the termination resistor points, although this isn't possible, since the ...
14
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3answers
2k views

Why are oscilloscope input impedances so low?

My question is two-fold: Where does the input impedance come from? I'm wondering where the input impedance of your average multimeter or oscilloscope comes from? Is it just the input impedance to ...
19
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5answers
4k views

CRT Oscilloscope - part of the plot is missing

I picked up an old METRIX OX 720 oscilloscope. I replaced 2 capacitors that went up in smoke. Once restarted, here is the signal I get. The vertical part of the signal is missing. It is the same ...
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0answers
83 views

Build a high voltage probe to calibrate a 1.5 kV oscilloscope CRT supply voltage

I want to build a high voltage probe to calibrate my 1.5 kV oscilloscope CRT supply voltage. Will just use this probe once to calibrate the scope so I don’t want to spend $200 on a probe and I mind ...
0
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3answers
177 views

AD620 pH probe has a positive voltage offset!

I am a chem eng. but little background in electronics. I'd like to interface a pH probe with an AD620A, the original PCB that came with pH probe was damaged by a current leak in the solution. I made ...
0
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1answer
852 views

Adding a second Y axis to an LTSpice plot

I am new to using LTSpice and am coming over from using Cadence. In Cadence you can add a second Y axis. Plot-> Add Y Axis is the probe pane in Cadence. Is there a way to do this in LTSpice?
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2answers
103 views

Oscilloscope probe pF values

I bought some time ago a 2nd hand Philips PM 3253 including probes which shows on the oscilloscope probe inputs: 1 MOhm, 20 pF While the probes I got with it ...
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2answers
238 views

Is this type of scope probe homemade? [duplicate]

To reduce the loop area and noisepick up, the GND lead of the scope probe is very next to the tip in the below probe: I don’t have such probes and my scope probe GND leads are much longer alligator ...
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0answers
46 views

Schematic diagram probe question

I am not sure whether to call it a probe on my schematic diagram or is it something else. I have ATmega328P checking its two digital pins whether both have been connected to the ground. When floating,...
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0answers
184 views

TMC2130 IC only working when being probed

I designed a small shield for a Wemos D1 mini and a TMC2130 SilentStepStick. After the ESP boots up, it is supposed to initialize the TMC2130 via SPI to move a stepper motor afterwards. My problem is ...
0
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1answer
164 views

Oscilloscope Probe - How to measure a sensitive circuit

Help needed in measuring a tiny piezo actuator. The circuit bangs the actuator with a voltage ( max 50V ), then senses the ripples after the initial actuation. How can I measure with an oscilloscope ...
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2answers
144 views

Can I use any HV Probe for a Voltmeter/Ampmeter gauge?

I purchased the multimeter pictured below for a high voltage power supply I'm working on. It's rated for 100V DC and 10A, but I hope to measure several thousand volts. Is it possible to use a HV ...
3
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1answer
203 views

What effect does a logic analyzer probe have on a circuit?

I have an MCU controlling a LED sign. This sign speaks the HUB75 protocol, which is essentially a large shift register. Being a shift register, this requires a clock signal to be generated, which the ...
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3answers
210 views

Adding Debug LEDs to PCB

I'm working on the next revision of a prototype PCB board, and from the first one I learned that LEDs would be very helpful instead of having to probe each pin/wire for a certain state. In this ...
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2answers
85 views

Can you receive a shock by touching only one probe ?

in this video at 4min 4sec https://youtu.be/CkGVMWK10qU?t=243 The guy receive a shock of a taser by touching a metal object that touches one probe, but why does the arc goes through his body ? I know ...
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3answers
1k views

How the low inductance of short ground clip probes prevents interference?

Below are photos of two scope probes with different ground clip lengths: I have read that the shorter ground is used to minimize the inductance of the probe ground lead. But what does that help for? ...
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2answers
962 views

Oscilloscope: when to use coaxial instead of probes?

I understand the difference between passive and active probes, and between x1, x10, x100, ... I also understand that at high frequencies the capacitance of the oscilloscope has to be considered, so a ...
9
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3answers
2k views

Does this experiment show that Kirchhoff's Law hold when there's a changing magnetic field involved in a circuit?

In this video, the electrical engineer and youtuber Mehdi Sadaghdar (ElectroBOOM) disagrees with another video from professor Walter Lewin. Basically, professor Lewin shows in an experiment that if ...
4
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1answer
263 views

What is the proper name for this oscilloscope probe accessory?

These used to come standard in the accessory pack that comes with a new o'scope probe, but they haven't been included in quite some time. They are very useful for checking certain test points, and we ...
1
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1answer
63 views

FLUKE 15b+ fuse test

I have accidentally shorted my circuit (5 Volt Vcc) for approximately 1-2 seconds max. While the circuit was short circuit I use the FLUKE as ampermeter in miliAmper mode (400mA max fused) The current ...
1
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2answers
262 views

How do current probes load a circuit?

It's usual to talk about loading a circuit when measuring voltage, with a voltmeter or with a voltage probe and an oscilloscope. It can be seen as putting an impedance in parallel to the element whose ...
2
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1answer
173 views

Segger ATSAME54N20 SWD error

INTRODUCTION I'm trying to program a custom board I designed, featuring a SAME54N20 MCU. My programming probe is a J-Link EDU (version 10.1), connected to my board using a Olimex adapter with a 10 ...
3
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1answer
416 views

How does capacitive coupling work for measurements

The context is the measurement of engine speed on a vintage car that uses a classic Kettering ignition system. Essentially, a voltage pulse of tenths of kV is generated on a high tension (HT) lead. ...
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2answers
1k views

Measuring differential signal with single ended probe

I have a differential signal(a +/- signal) to measure. Can I use a single ended probe to measure it and then just multiply whatever I read by 2 to get the actual amplitude?
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1answer
141 views

Oscilloscope differential measurement for battery powered circuit using single probe

I want to measure the voltage across a resistor in my circuit. The circuit is battery powered. I don't want to use the two probe method and calculate A-B to get the results. Can I use one probe to ...
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1answer
1k views

Why is an oscilloscope's Attenuation switch placed on the probe?

I'm wondering why an oscilloscope's Attenuation switch is placed on the probe not on the oscilloscope's body (like the AC/DC Coupling switch that's placed on the scope body not on the probe)?
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1answer
56 views

Why is the logic probe reducing current from the power supply?

I am troubleshooting a very basic circuit using an inexpensive logic probe to check values. Typically when I use the probe I see current output go up about 7mA, which I assume is to power the sound ...
3
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3answers
2k views

Why am I getting a half-wave rectified output when i am using a full-wave rectifier?

I have recently gotten back into electronics and have access to a lab with a signal generator and oscilloscope. I have been trying to teach myself how to use this equipment by building small and ...
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2answers
130 views

Probes gives different results

I discovered an "funny" thing today. I had used a GW instek probe GTP-150B-4 150Mhz in 10x mode and documented the result. Today I noticed in the testing department that what I've measured doesn't ...
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2answers
1k views

Probe circuit for measuring higher voltage on oscilloscope?

The only oscilloscope I have is a tiny DSO138 (input section is on the top left of page 4 in the linked PDF). The scope has a limit of 100Vpp (actually displays only 80Vpp). At the highest attenuation ...
0
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1answer
65 views

i2c probe happens only alternatively

I have connected a NXP NFC Module (pn7120) over I2C to i.MX6 Board. I tried to check whether the device is detected in the i2c probe command. It didn't detect in the first call, but got detected in ...
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3answers
130 views

HF signal in a null experiment. What is the exact mechanism?

Since I've tried to experiment with electronics, I am faced with the problem of HF noise and signals bypassing almost anything I try to stop them. This begun with my attempts to filter the noise of a ...