Grandpa
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Grandpa 25/08/2022
I was a bit unhappy at first as I was not able to download the manual and my unit arrived with a cracked case. I began to investigate it and repair it. The instructions available on the sales page provided enough information to set the unit up and running some tests. The unit works better than I had expected. I was able to determine the frequencies used. Low = 62 Hz Med = 234 Hz Med 2 = 2 kHz and High = 14.5 kHz. The red knob selects one of 4 different internal resistances. The A/B push button turns on and off the dual channel mode so that you can easily compare one circuit board position to another. The Blue knob adjusts the position of the "B" Channel image on the scope screen. I added a power switch to the unit so that it could be left plugged in when I wanted to. I also added some English Labels and non-slip feet for the back so that it doesn't slide around on the bench. The only item I have not been able to identify is a Blue Jack on the front that is labeled "G" on the front and "T" on the internal board. If anyone has figured what the "G" Jack is please let me know. I wrote a complaint to Banggood about the inability to down load the Manual and about a week later they sent me the pdf file. Unfortunately it did not identify the "G" jack. Over All I am very pleased with the unit and the way it functions. I would recommend it to anyone who has a curiosity about curve tracers and a scope capable of X-Y operation.
Dual-channel VI Curve Tester, Displaying 2 Waveforms at the Same Time for Easy Comparison
US$34.99 US$45.99
4
Recommendations
Comments (2)
Grandpa 01/07/2022
I was very satisfied with these batteries. Unlike many brands the Nominal rating of 3000 mAhr was accurate. When I ran a power test I got a reading of 2920 mAhr. The batteries also weigh a little more than many of the batteries that are being sold. The batteries from this order were about 46 gm. I felt it was a very good buy and I will buy more in the near future.
4Pcs Astrolux® C1830 3000mAh 3.7V 18650 Unprotected Li-ion Battery Rechargeable Lithium Power Cell 9.6A High Performance For Nitecore Lumintop Fenix Olight Flashlights RC Toys
US$27.99 US$29.99
0
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Comments (0)
Grandpa 29/07/2020
OK
3pcs LM393 3144 Hall Sensor Hall Switch Hall Sensor Module for Smart Car Geekcreit for Arduino - products that work with official Arduino boards
US$5.99 US$7.99
0
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Comments (0)
Grandpa 29/07/2020
OK
Electronic Dice Kit with Reverse Connection Protection LED Dice DIY Electronic Parts
US$6.99 US$8.99
0
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Comments (0)
Grandpa 29/07/2020
OK
DIY NE555 Ding Dong Bell Doorbell Module Kit DIY Music DIY Electronic Production Training Kit
US$2.49 US$2.99
0
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Comments (0)
Grandpa 29/07/2020
OK
Infrared Parking Sensor Kit Infrared Reversing Speed Reminder Electronic PCB Circuit Board Production DIY Kit
US$7.99 US$9.99
0
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Comments (0)
Grandpa 29/07/2020
If you have purchased this kit to test or improve your soldering skills do not be too hard on yourself. The traces on the circuit board are very fragile. I have years and thousands of hours of soldering experience and I had to repair 4 traces that broke while the unit was being assembled. The slightest torque on any of the components or LEDs causes the trace to lift from the board and break. Use a continuity meter to test your traces if the unit doesn't work and then use clipped leads to jumper across the breaks in the traces. You can't beat the price so forgive yourself on this one if it does't work right out of the gate. Also be aware that CCW on the trimmer increases sensitivity and CW decreases the sensitivity.
LM3915 10-segment Audio Level Indicator Kit Electronic Soldering Training experiment DIY Parts
US$2.99 US$4.49
0
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Comments (0)
Grandpa 29/07/2020
OK
3Pcs Electronic Dice Kit with Reverse Connection Protection LED Dice DIY Electronic Parts
US$6.25 US$7.50
0
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Comments (0)
Grandpa 29/07/2020
OK
DIY Touch Vibration Alarm Kit Electronic Training Teaching
US$2.99 US$3.99
0
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Comments (0)
Grandpa 07/02/2020
I am quite pleased with this power supply control board except for one problem. The circuit is designed to use (3) TL081 Op Amps which have an Offset circuit built in. The Offset is necessary in the U2 position (lower right hand corner above the blue trimmer) if you want to bring your voltage to zero volts when the voltage control is all the way down. Unfortunately the TL081 chips that are currently being supplied with the kit are not quality and they do not have the Offset circuitry built into the chip. If you want to be able to zero your voltage output when the voltage control is all the way down you will have to purchase a quality TL081 chip for this position. At the price they are selling these kits for this is a small problem and easily remedied. John
0-30V 2mA - 3A Adjustable DC Regulated Power Supply Module DIY Kit
US$4.99 US$9.59
0
Recommendations
Comments (0)
Grandpa 23/01/2019
I have ordered these M-Testers a couple times and I have generally had good luck with them. The plastic cases make them a lot more usable and attractive. This batch however had one unit that didn't work properly. Looks like the Atmel chip is defective but at the cost per unit it is no problem.. I will use it for spare parts. A second problem with each unit seemed more serious. The test socket contacts would not open all the way. After removing the sockets from the board and checking them out I found that they worked just fine once they were removed from the board. The source of the problem was that the sockets had been soldered to the board by the manufacturer while in the closed position. This holds the contacts to one side and when the socket is soldered the solder holds the pins towards the closed side and doesn't allow them to open. The solution if you are having this problem is to simply open the test socket and heat up the solder to each pin to allow the pin to come to its normal open position. John
Geekcreit® LCR-T4 Mega328 Transistor Tester Diode Triode Capacitance ESR Meter With Shell
US$9.99 US$21.99
0
Recommendations
Comments (1)
Grandpa 15/10/2018
These buttons are momentary, not latching! The information supplied is contradictory as it states both latching and momentary. They are also small like the typical small key switch with an LED under the button.
Power Symbol Latching Switch LED Light Push Button SPST
US$6.99 US$8.99
0
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Comments (0)
Grandpa 27/09/2018
This is a normally open momentary switch.
Wendao R13-507 125V 6A 16mm No Lock Self-reset Switch Push Button OFF/ON 10pcs
US$13.99 US$16.99
0
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Comments (0)
Grandpa 26/07/2018
I was a little surprised by how small the cutters were, only 3.75 inches from pointed tip to end of handle but they cut very well and were well machined. I was able to cut typical leads at the very tip of the jaws with no problems. The small size may even be an advantage. John
DANIU Mini Pliers Hand Tool Diagonal Side Cutting Pliers Stripping Pliers Electrical Wire Cable Cutters
US$3.59 US$9.99
0
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Comments (0)

Grandpa Sorry I missed your question earlier. 24cm wide X 9 cm high X 26 cm deep with approx 4 kg.John

Grandpa 29/08/2017
This is a very versatile and useful basic power supply circuit. So far I have used it to build several dual bench power supplies and other specialized test equipment. Lots of fun.
0-30V 2mA - 3A Adjustable DC Regulated Power Supply Module DIY Kit
US$4.99 US$9.59
7
Comments (2)
Grandpa 11/04/2018
I think this is the nicest little meter I have ever owned. It has features and accuracy found on meters 10 to 20 times more expensive. It even has an EM field detector so you can tell when a conductor is hot with lethal voltage. The only problem I had is that one of the internal fuses had popped out of its clips during shipping so I had to open the case and put it back in place. John
BSIDE ADM66 True RMS Digital Multimeter Auto Range TRMS Mini 6000 DMM Dual Slot Capacitance ohm Hz Temp NCV Diode Pocket Tester MUSTOOL MT66
US$20.13 US$24.16
0
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Comments (0)
Grandpa 21/03/2018
I bought 5 of these and they are working great. My 11 year old grandson built one the other day and it turned out good after we discovered he had switched one 8550 with an 8050. It is nice when a mistake like this doesn't cause anything to burn up. After putting things where they belonged it worked well. We mounted it on a 6 volt battery box with a power switch and he had a nice little project to show at school.
5Pcs Electronic Dice DIY Kit 5mm Red LED Interesting Parts NE555 CD4017 Electronic Production Suite
US$13.99 US$16.99
0
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Comments (0)
Grandpa 21/03/2018
As noted by other reviewers the circuit doesn't work well as designed but I do not agree with them as to how to fix it. R-2 39K has the purpose of introducing hysteresis into the circuit, however it creates way too much and extreme temperature moves are necessary to make it work. Just changing R2 from 39K to 100K brings the hysteresis down to 4 degrees C. The LED should have a current limiting resistor and there is a problem with Q1 overheating if the transistor is turned on to saturation by the variable resistor. Keep the variable resistor away from the 0 ohms end of its travel. This circuit was a lot of fun since it didn't work and took some study and experiment to make it function. For the price I had a lot of fun.
Temperature Control Sound Light Alarm Kit DC3-5V Electronic Circuit DIY Training Suite
US$2.43
2
Recommendations
Comments (1)

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