LCD 2v or 20V DC/AC meter, Lightobject Part EPM-8035B20V

tonka1020
Posts: 6
Joined: Sat Mar 17, 2012 6:39 am

LCD 2v or 20V DC/AC meter, Lightobject Part EPM-8035B20V

Postby tonka1020 » Mon Mar 19, 2012 8:05 pm

I recently purchased a 8035 LCD volt meter. I was most interested in it's 2v setting, which if I read it properly should allow me to measure 0-1.999 volts with a .001 resolution.

When I change Dip5, the meter then maxes out at 200mV. I set up a bread board and a Potentiometer so that I could run the voltage up and down. The 8035, with Dip 5 adjusted (and dip 1 to adjust the dec point) reads 1.444 (where the potentiometer happens to be set). I checked this with an a standard voltmeter and the voltage is 1.44mV

I need to be able to measure 0 - 1.999v

I have read and re-read the listing, and I just picked something up. It's a 8035 Meter, but under the details it's listed as a 8105. Typo or Listing error?

I really need to get this solved soon. Thanks!

Tech_Marco
Posts: 4311
Joined: Mon Jun 15, 2009 3:00 pm

Re: LCD 2v or 20V DC/AC meter, Lightobject Part EPM-8035B20V

Postby Tech_Marco » Wed Mar 28, 2012 10:43 pm

Contacted the manufacturer last night and was told that it could be done pretty esay by changing a resistor underneath of the IC from 1M ohm to 100 Kohm. It's one that closed to the DIP switch. I'll try to make one up tomorrow if I can spare out some time

Marco

tonka1020
Posts: 6
Joined: Sat Mar 17, 2012 6:39 am

Re: LCD 2v or 20V DC/AC meter, Lightobject Part EPM-8035B20V

Postby tonka1020 » Thu Mar 29, 2012 5:58 am

Tech_Marco wrote:Contacted the manufacturer last night and was told that it could be done pretty esay by changing a resistor underneath of the IC from 1M ohm to 100 Kohm. It's one that closed to the DIP switch. I'll try to make one up tomorrow if I can spare out some time

Marco


Outstanding!!!! Can you show me which one it is (in a picture) and I will make the modifications to the ones I already have?

Please note, there is a difference between the LCD and the LED meters, and I have both! The boards look quite different!

Thank you very much for taking care of this.

tonka1020
Posts: 6
Joined: Sat Mar 17, 2012 6:39 am

Re: LCD 2v or 20V DC/AC meter, Lightobject Part EPM-8035B20V

Postby tonka1020 » Thu Mar 29, 2012 7:04 am

And I forgot to ask, what wattage of resistor? I know they are small, I just need to order the correct one so it fits!

Tech_Marco
Posts: 4311
Joined: Mon Jun 15, 2009 3:00 pm

Re: LCD 2v or 20V DC/AC meter, Lightobject Part EPM-8035B20V

Postby Tech_Marco » Thu Mar 29, 2012 11:23 pm

I figured out that the resistor should be 100K in order to show 2V when DIP SW is at 'Off' position. If DIP#5 On, it will multiple the voltage by 10 times.

I tested two meter: LCD 20V and LED 20V. Surpised me that the LCD showing "2V" when DIP SW was set to Off. But I need to change the deciminal point to show 1.999V though. But for the 8135 LED meter, it's 200mV. So, I think either they used wrong resistor by mistake or they did that in purpose.

Anyway, use a 100K resistor 1/4Watt to replace the resistor that I high lighted by yellow line


Marco
Attachments
8035LCD.jpg
8135LED.jpg

tonka1020
Posts: 6
Joined: Sat Mar 17, 2012 6:39 am

Re: LCD 2v or 20V DC/AC meter, Lightobject Part EPM-8035B20V

Postby tonka1020 » Thu Apr 05, 2012 4:00 pm

Outstanding.. That is what I needed..

Thanks for getting back to me in a timely manor..

t


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