# LCR Pro1 Plus

#### bob2

Joined Jun 15, 2019
139
Hi all.
Yesterday I received this meter of electronic components. I began to study his work. Everything seemed to be fine and expected, even better than I thought.
But there is no large experience of measurements directly in circuit. Therefore, I decided to ask a question on the forum.
In measurements in circuit, you can use a voltage of 0.5 volts or only 0.2 volts?
Indeed, as is known, the accuracy of the measurement depends on the magnitude of the voltage.

#### SLK001

Joined Nov 29, 2011
1,529
Excellent specs on that device. My only concern is the OLED display. In my experience, they don't have very good longevity. What does something like this set you back?

#### JohnInTX

Joined Jun 26, 2012
3,816
I paid about $300 for mine. Like it a lot. Thread Starter #### bob2 Joined Jun 15, 2019 139 Excellent specs on that device. My only concern is the OLED display. In my experience, they don't have very good longevity. What does something like this set you back? Compared with LCD displays, it is much clearer and brighter and does not depend on the illumination. The displayed information is clearly visible from any angle. Now I will tell you my opinion regarding the operating time of these OLED displays. I hope that the production technologies have reached such a level that there is no doubt about their durability. I hope, in this universal meter of electronic components, the manufacturer has applied a very high-quality display, which will not create problems. Thread Starter #### bob2 Joined Jun 15, 2019 139 I paid about$300 for mine. Like it a lot.
My cost was about the same.
Every day I’m more and more convinced that the money was spent not for nothing. Very good investment, looking into the future.

#### bob2

Joined Jun 15, 2019
139
Hi
I will repeat my question. Maybe someone will clarify the situation.
In measurements in circuit,i can use a voltage of 0.5 volts or only 0.2 volts?

#### rsjsouza

Joined Apr 21, 2014
211
Hi
I will repeat my question. Maybe someone will clarify the situation.
In measurements in circuit,i can use a voltage of 0.5 volts or only 0.2 volts?
Although 0.2V is probably harder to get an accurate measurement (lower noise margin), 0.5V is too close to activate the P-N junctions in nearby semiconductors, which will surely affect your measurements.

I personally don't encourage anyone to test anything in circuit, but between the two, I would perform my tests with 0.2V.

#### bob2

Joined Jun 15, 2019
139
0.5V is too close to activate the P-N junctions in nearby semiconductors, which will surely affect your measurements.
Can you describe this situation in more detail? Which semiconductors, and under what circumstances, can influence the measurement results, given the difference of 0.3V.
Perhaps those who use this electronic component meter for some time can share their experience with in-circuit measurements.

#### BR-549

Joined Sep 22, 2013
4,938
Why would you use device in circuit? What would be the purpose?

It can only verify the value, when component is isolated.

One can not verify value in circuit. Because it becomes a circuit value, not a component value.

But you can verify operation in circuit. Just not with that tool.

One can verify a component in circuit(not value)....and can verify circuit operation.

All that is needed is a small ac voltage and an X-Y scope.

#### bob2

Joined Jun 15, 2019
139
In the manual on the device there is no ban on measurements in the scheme.
There is only a warning about the possible influence of other components.
But this is understandable, because the manufacturer can not one hundred percent guarantee the accuracy of the result in all cases of measurements in circuit.
This is written in the manual.
"When doing in circuit testing,the test result may be affected by other components that connect to the component under test.The component under test may need to be isolated from other components in order to get accurate result."

#### rsjsouza

Joined Apr 21, 2014
211
Can you describe this situation in more detail? Which semiconductors, and under what circumstances, can influence the measurement results, given the difference of 0.3V.
Perhaps those who use this electronic component meter for some time can share their experience with in-circuit measurements.
Several, if not all, modern ICs have ESD protection clamp diodes that limit the damage caused by a discharge on their pins.Given these diodes are usually tied to the power supply (internally to the IC) and the LCR meter outputs an AC signal, there is always a chance the current used to calculate the resistance or the voltage ramp used to calculate the capacitance will be influenced by these components in parallel.

Another scenario is illustrated attached, where the measurement will not only be influenced by the current across the resistor network (R3, R4, R5) but a higher LCR voltage will activate the PN junction of the base of Q2.

Many other examples to count. That is why the manufacturer gives this warning.

At any rate, both 0.3 and 0.5V are quite low for that. Kudos to the manufacturer.

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#### bob2

Joined Jun 15, 2019
139
Another scenario is illustrated attached, where the measurement will not only be influenced by the current across the resistor network (R3, R4, R5) but a higher LCR voltage will activate the PN junction of the base of Q2.
Please indicate the required values on the diagram, I will try to make this diagram on the layout. Let's see what the LCR meter shows.

#### bob2

Joined Jun 15, 2019
139
I am studying the problems of in-circuit measurements. I collect and analyze various data sources that are on the Internet. I will tell you straight, there is very little useful information.
This is the situation that occurs in the diagrams, which may present certain difficulties for the LCR meter.
View attachment 180034

#### bob2

Joined Jun 15, 2019
139
Here is the situation.

#### BR-549

Joined Sep 22, 2013
4,938
May I ask what engineering field you're in? Some components have a cancelling effect on other components.

When components touch, they marry and become one.

#### bob2

Joined Jun 15, 2019
139
Having worked a little with the device, I understood its main positive quality, which is very important for me to work. This is an automatic measurement mode for electronic components. The device automatically determines the type and value of the component by selecting the appropriate function.
This is a very useful thing, given the lack of marking of small inductances and ceramic capacitors.
Remembering the designation of resistors is also not necessary.
To check the electrolytic capacitors, the device automatically selects the desired measurement frequency.

#### SHA_S

Joined Jun 20, 2019
15
It would not be bad, if with a capacity, tweezers immediately showed a capacitor ESR at 100 kHz. This would significantly reduce the time for checking the capacitors on the board. Still it is interesting what losses this tweezers show in ceramic capacitors of small capacity (1-4pF) at a frequency of 10 kHz?