Products > Test Equipment
Mastech MS5308 LCR meter with ESR measurement - on discount at the moment
<< < (35/51) > >>
PA4TIM:

--- Quote from: nixxon on January 18, 2013, 05:51:07 pm ---Is the power supply problem really a problem?



--- End quote ---
No, not in practice  but for a 200 dollar LCR meter I would not accept this. Makes you wonder about the rest of the design. For instance if you have a charged cap, or static, or just EMC problems. But what bothers me the most is the measurements are influenced by the powersupply. So what happens if your battery voltage drops, or you use rechargable cells (so a 0.3V per cell lower voltage)
PA0PBZ:

--- Quote from: nixxon on January 18, 2013, 05:27:33 pm ---I wonder what the resistance is between either side of "R16" and "GND".

--- End quote ---

It looks like the wire is connected to ground, my guess is it was just easier to solder it to the resistor than to the connector hole.
alm:

--- Quote from: nixxon on January 18, 2013, 05:27:33 pm ---I wonder what the resistance is between either side of "R16" and "GND".

--- End quote ---
I seem to remember that they were directly connected by a PCB trace.


--- Quote from: nixxon on January 18, 2013, 05:27:33 pm ---Maybe the PCB was designed for 9 volts external power (less than 12 volts) and Mastech made this ingenious setup for the meter to handle a 12 volt power supply that was already designed for some other gadget? I am of course just speculating here...

--- End quote ---
It will just display low battery and switch off at either 9 V or slightly below it.


--- Quote from: nixxon on January 18, 2013, 05:51:07 pm ---Is the power supply problem really a problem?

--- End quote ---
You can't disable auto power off except by connecting an external power source, as far as I know. I'm sure you could install a switch that would trick the meter into thinking it was fed by AC power.
robrenz:

--- Quote from: PA4TIM on January 18, 2013, 05:17:45 pm ---But today I ordered the IET DE5000.

--- End quote ---

I anxiously await your assessment of its functionality and accuracy. I know mine is exceptionaly accurate on low ohms but you will be able to check it all ;D
nixxon:

--- Quote from: alm on January 18, 2013, 06:54:53 pm ---

--- Quote from: nixxon on January 18, 2013, 05:27:33 pm ---Maybe the PCB was designed for 9 volts external power (less than 12 volts) and Mastech made this ingenious setup for the meter to handle a 12 volt power supply that was already designed for some other gadget? I am of course just speculating here...

--- End quote ---
It will just display low battery and switch off at either 9 V or slightly below it.

--- End quote ---

I meant that without the "R16-mod", the meter might accept lower voltage, like 6 - 12 volts from a 9v supply.
With the "R16-mod", the meter may need higher voltage, like 9 - 15 volts.

Who knows; maybe the R16 resistor is ground (at wire solder joint side) as suggested. Maybe the the negative power lead was just too short to reach the "GND" point without possibly touching the +12V wire.
Navigation
Message Index
Next page
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod