RoadTest: Cool Tools: Pen Type Digital Multimeter
Author: dixonselvan
Creation date:
Evaluation Type: Test Equipment
Did you receive all parts the manufacturer stated would be included in the package?: True
What other parts do you consider comparable to this product?: Shanghai Mastech MS8211D ($19.95), UNI-T UT118A ($22) - There is no visual difference in appearance between this multimeter and the road test unit, the road test unit Tenma pen style meter 72-9390 is priced at $36.59. The prices mentioned here are taken from Amazon.com as on July 29, 2018.
What were the biggest problems encountered?: 1) The power cum mode (Voltage measuring mode/ Resistance, Diode, Capacitance and Continuity testing mode) switch is hard to slide. When we slide it, it moves to the other extreme and does not stop in the middle at times. 2) The Display has edges which are a bit curved at the edges which limit the angle of vision and makes it hard to read unless you have the backlight turned ON.
Detailed Review:
Last Modified Date & Purpose - August 09, 2018 & Road Test Review Creation
Introduction
Like the stethoscope for a doctor, multimeters are for Electrical/ Electronics engineers. Multimeters come in various sizes and models, manufactured by different manufacturers. The common multimeters are like the one in the picture #1 [Tenma 72-2595] below. Have you ever struggled while using one of them? Let me tell my reason for the struggle. These kinds of multimeters have a display with a multimeter unit and the probes separate. Whenever you need to have a look at the value of current/ voltage across components in your PCB, you have to locate them using the probes and then look at the display in the multimeter unit. During this process, sometimes you tend to move the probes away unknowingly from the expected position and then you have to relocate the probes again. Some have alligator clips to hold the probes in place. But still, we have some components where we can not use clips to hold and need the probes to be held in position. Also, what if the location where your PCB is mounted does not have proper lighting? Either you need to light the area using a torchlight or you have to take the PCB out.
#1 - Common Multimeter #2 - Pen Style Multimeter
But what if your multimeter, probe, and a torchlight are combined together? See it in the picture #2 [Tenma 72-9390] above, the handheld Tenma pen style digital multimeter priced around $37. Also, Tenma is not the only company which manufactures this type of multimeters. See some of the similar products above, under the title - ‘Comparable Products/ Other parts you considered’.
To know more about multimeters, I suggest to check out the Wikipedia article in this link. This will be my road test review of the Tenma 72-9390 pen style digital multimeter. Click here if would like to know About me.
Table of Contents
The road testing process of this pen style multimeter is split into the below stages along with duration to complete, as per the plan proposed in the road test review application. As usual for every other road test I do, the first would be an unboxing and the out of the box experience video. Next is to test the functionalities mentioned in the product's package case followed by a comparison with the multimeters that I have.
The package arrived in great form. Thanks to rscasny, Element14 community and UPS for the delivering the product safely. Inside the package case, we have
The multimeter unit has a black body and an orange top. This is a positive probe continued with a display. It has functional buttons and a switch at the front. We have options to insert battery at the back. The ground/ negative probe is pretty good in quality and comes with a cap to protect the lead when not in use. The operating manual has all the pieces of information to get started out of the box along with safety precautions and warnings. Check out the video below for the Unboxing of the Tenma pen style digital multimeter.
This section has contents that have been taken from the Operating Manual.
The Tenma 72-9390 uses a large-scale Integrated circuit with professional multimeter IC as its core and has full range overload protection. This a 3000 counts pen type digits multimeter which means the maximum value that can be displayed is 2999. The meter is compliant with the EN61010 standard: in pollution degree 2, overvoltage category (CATIII 300V) and double insulation. CAT.III: Distribution level, fixed installation, with smaller transient overvoltages than CAT.IV.
The below image explains the various parts of the multimeter. It has a positive lead at the front top inside an orange cap. Pull down and twist the orange cap counter-clockwise to expose the input terminal. This is followed by the functional buttons which are as follows:
Then, we have a slide switch to switch between the various mode (Voltage / Resistance, Capacitance, Diode, and Continuity test mode) and it is can be used to turn off the meter manually. By pressing and holding the select button, the meter enters into sleep mode. It has a non-rotatable fixed LCD display with backlight.
This section has contents that have been taken from the Operating Manual.
Function | Range | Best Accuracy |
---|---|---|
DC Voltage | 3V/ 30V/ 300V | ±(1%+3) |
AC Voltage | 3V/ 30V/ 300V | ±(1%+4) |
Resistance | 300Ω/ 3KΩ/ 30KΩ/ 300KΩ/ 3MΩ/ 30MΩ | ±(1%+3) |
Capacitance | 3nF/ 30nF/ 300nF/ 3µF/ 30µF/ 300µF | ±(3%+5) |
AC/ DC voltage
To avoid damage to the meter, never input greater than 300 voltage
The maximum voltage which could be measured without damaging the meter is 300V. To measure AC/ DC voltage, you have to do the following steps:
To avoid damages to the meter or to the devices under test, disconnect circuit power and discharge all the high-voltage capacitors before performing the below measurements/ tests
Resistance
To measure the resistance, you have to do the following steps:
Capacitance
To measure the capacitance, you have to do the following steps:
Function | Range |
---|---|
Sleep Mode | |
Auto Ranging | |
Input Impedance for DC Voltage Measurement | ≥ 10MΩ |
Diode | |
Full Icon Display | |
Continuity Buzzer | |
Sleep Mode | |
Max/ Min Mode | |
Data Hold | |
Display Backlight | |
Low Battery Display | |
Max Display | 2999 |
Sleep Mode
To preserve battery life, the meter automatically goes into a 'sleep mode' if you do not press any button for around 10 minutes. The meter can be activated by pressing any button, then it returns to the display for the function selected previously.
To avoid damages to the meter or to the devices under test, disconnect circuit power and discharge all the high-voltage capacitors before performing the below measurements/ tests
EF Function
To measure NCV, you have to do the following steps:
Diode
To perform the Diode test, you have to do the following steps:
Continuity Test
To perform the Continuity test, you have to do the following steps:
Below is the comparison chart of functionalities, specifications, and quality of Tenma 72-9390 (Pen Style Meter), Tenma 72-2595 and a cheap DT830D multimeter.
| Tenma 72-9390 | TENMA 72-2595 | DT830D |
Voltage Measurement (DC) Maximum/ MINIMUM value: | Yes (Auto-Ranging) 300V/ 3V | Yes 600V/ 200mV | Yes 1000V/ 200mV |
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Voltage Measurement (AC) Maximum/ MINIMUM value: | Yes (Auto-Ranging) 300V/ 3V | Yes 600V/ 2V | Yes 1000V/ 200V |
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resistance Measurement Maximum/ MINIMUM value: | Yes (Auto-Ranging) 30MΩ/ 300Ω | Yes 20MΩ/ 200Ω | Yes 2MΩ/ 200Ω |
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Current Measurement (dc) Maximum/ MINIMUM value: | NA - | Yes 10A/ 2mA | Yes 10A/ 2000µA |
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Current Measurement (Ac) Maximum/ MINIMUM value: | NA - | Yes 10A/ 20mA | NA - |
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capacitance measurement Maximum/ MINIMUM value: | Yes (Auto-Ranging) 3mF/ 3nF | Yes 200µF/ NF | NA - |
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Special functions | Sleep mode, Auto Ranging, Low Battery display, Diode, Continuity Buzzer, EF Function, Max/ Min mode, Data Hold, Display Backlight, Test lead LED | Sleep mode, Temperature measurement, Low Battery display, Diode, Continuity Buzzer, Data Hold | Sleep mode, Low Battery display, Diode, Continuity Buzzer, |
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Operating manual | Yes | Yes | No |
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Probe Quality | |||
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Build Quality |
Below is the video showing the comparisons and functional tests performed using Tenma pen style multimeter and two other meters.
I am glad that I received this wonderful multimeter. This is small, portable and with all the required functionalities with desired specifications. Below are some of the pros and cons that I have noticed during the two months of this road test.
Pros
Cons
With this ends my review of the Tenma 72-9390 Pen-Style Meter.
Top Comments
Nicely written
Thanks snidhi
Hi Dixon,
A really well written review (detailed and easy to read). Looks like a useful piece of test equipment.
Rod