Hello
I have Mastech MS8222H multimeter.I usually match some 10nf and 100nf capacitors with this.But the values changes by room temperature.Can i make any modification by changing resistors in it?(I have some 5ppm leaded resistors)Can i modify this and make it a better multimeter?
I do not know how it works when measuring film caps.Maybe it works like a RC circuit right?
Thanks
I have Mastech MS8222H multimeter.I usually match some 10nf and 100nf capacitors with this.But the values changes by room temperature.Can i make any modification by changing resistors in it?(I have some 5ppm leaded resistors)Can i modify this and make it a better multimeter?
I do not know how it works when measuring film caps.Maybe it works like a RC circuit right?
Thanks
Have the same problem here , ( was 40C today , tomorrow 43C)
Easy to solve , buy an accurate thermometer and measure at 20 degrees C
Have a big airco in my room and set it on 20 and wait .
Your capacitors wont have the same capacity with different temperatures . Have a look at the datasheet of your capacitors and look at the thermal specs .
The problem is probably not in your multimeter .
Cheers ,
Rens
-Hehe.Another part of the world.It is around 10C here.Let us make a tunnel between your room and my room
The caps are mkp1837 and kp1830.
for mkp1837 temp coeff is - 250°C x 10-6/°C (typical value)
When i measure by multimeter in cold it is 102 nf and in hot it is 100nf.The difference is around 20celcius degree.So it makes around 0,5% difference in capacitor
But in total measurement it makes 2% difference.Regards
The caps are mkp1837 and kp1830.
for mkp1837 temp coeff is - 250°C x 10-6/°C (typical value)
When i measure by multimeter in cold it is 102 nf and in hot it is 100nf.The difference is around 20celcius degree.So it makes around 0,5% difference in capacitor
But in total measurement it makes 2% difference.Regards
is it the multimeter that's drifting or the capacitors or both? Put the meter in a fridge. wait a couple of hours. Take your capacitor readings. Is there any difference in the capacitor reading with the meter in the fridge or the meter outside at ambient. Remember your circuit will be in some kind of a box which will be heated by the air and any components inside. Where will the final project be?
Good, so you know that the reading of the multimeter drifts up with temp. Now keep the teperature of the meter constant and heat the capacitor. How much does it change. What will be the final circuit that uses the capacitors and how critical is the value. ie frequency shaping or coupling or bypass. How hot will it get in your enclosure.
You get a 3.6% drift for maybe a 30° temperature rise (perhaps more). So you can expect less than 0.36% drift if you keep the temperature of your meter within 3°. This should not be too difficult if you shield it from direct heat/airflow, and allow sufficient time for warmup.
If that's not good enough we'd need to see a schematic of the meter for an educated guess. Perhaps it's easier to derive a dedicated jig for capacitance measurement.
Samuel
I have some very precision resistors.Can i make some equipment with these.
I match resistors and capacitors for diyers.
1x New Genuine Vishay VHPT4Z 1 Ohm 1 001 Ohm 0 1 Extreme Hi End Resistor | eBay
I match resistors and capacitors for diyers.
1x New Genuine Vishay VHPT4Z 1 Ohm 1 001 Ohm 0 1 Extreme Hi End Resistor | eBay
Dear umut1001,
It`s not as simple to make a $50- multimeter into a precision referance lab meter by replacing a few resistors. You need a lab meter like this: 34401A MULTIMETER | eBay
It`s not as simple to make a $50- multimeter into a precision referance lab meter by replacing a few resistors. You need a lab meter like this: 34401A MULTIMETER | eBay
As has been suggested a bridge circuit would be a possibility if you have a stable AC voltage source and RMS meter. Alternatively you could build a precision relaxation oscillator if you have a DMM (or other means) which measures frequency. Take a precision comparator with CMOS output, power it from a stable voltage source (e.g. IC reference), set the nominal frequency to 1 kHz for a 10 nF cap und use 25 ppm tempco or better resistors. As most frequency measurement gear is pretty stable (referenced to a crystal oscillator), this should easily bring the drift of your setup well below that of the capacitors itself.
But again first make sure you can't achieve the desired result with good measurement practice.
Samuel
But again first make sure you can't achieve the desired result with good measurement practice.
Samuel
The Mastech is a toy of a meter. No offense but I haven't seen anything from Mastech that wasn't disappointing. Quite simply, if you want to do what you mention and do it properly you need a real LCR. The best value right now is the Der EE DE-5000. For around $130 you get a true high accuracy LCR with multifrequency abilities up to 100kHz. It has an accuracy of 0.3% on many ranges, automated sorting ability in as small as 0.25% bins, ESR, q, tan d, etc.
Also, Der EE is the OEM for the identically named IET DE-5000. IET is the manufacturer of a wide range of ultra precision measurement products.
Also, Der EE is the OEM for the identically named IET DE-5000. IET is the manufacturer of a wide range of ultra precision measurement products.
Hi.thank you for your help. There are many of them on ebay.Price range is from 90 to more than 130usd.What is difference between them? Which of them do you suggest to buy? Regards Umit
Sure, the differences are the accessories included.
There are four accessories:
Alligator Clips - for easy testing of leaded components
Tweezers - for testing smd components
Guard lead - not sure what this is for
USB data cable - self explanatory
So pick what you need and purchase the price point that fits.
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