R19 and R20

2nd harmonics for the masses

R19 and R20

Postby Spoon109 » Sun May 10, 2015 7:55 pm

Hello,

I have kind of noob question.

R19 and R20. The BOM calls out a 0.75 ohm 10% tol. wirewound resistor (71-CW2B-0.75).

The resistors I got from Mouser are part marked correctly, but it measures 0.9 ohms. Which is +20% tol. Is it ok to use this in my Get Set Go build?
Spoon109
 
Posts: 2
Joined: Fri Feb 06, 2015 3:15 pm

Re: R19 and R20

Postby EWBrown » Sun May 10, 2015 8:01 pm

With such low values of resistance, the resistance of the meter leads will add a couple of tenths of ohms resistance, which will then become quite noticeable.

Some DVMs allow this factor to be "zeroes" out.

HTH

/ed B
Real Radios Glow in the Dark
User avatar
EWBrown
Insulator & Iron Magnate
 
Posts: 6389
Joined: Wed Mar 19, 2003 6:03 am
Location: Now located in Clay County, NC !

Re: R19 and R20

Postby Geek » Sun May 10, 2015 9:35 pm

The resistors are probably correct and your meter is confused by lead resistance.

You can zero out the lead resistance on an analog with the "Zero" control.

On a DMM, such as my Triplett, you put the probes together and press the "Delta" button when it hits a reading of 0.000.

Your DMM is probably similar, check the manual.

If you have an el-cheapo DMM with no ohm-zero function, forget about measuring anything under 10-15 ohms.

Cheers!
-= Gregg =-
Fine wine comes in glass bottles, not plastic sacks. Therefore the finer electrons are also found in glass bottles.
User avatar
Geek
KT88
 
Posts: 3585
Joined: Sun Oct 21, 2007 3:01 am
Location: Chilliwack, British Columbia


Return to get*set*go

Who is online

Users browsing this forum: No registered users and 13 guests