Introduction: Check the Accuracy of Your Multimeter Voltage
By using a LT1021 chip and a couple of 100 nF capacitors you can solder together this circuit to test the voltage accuracy of your multimeter for almost no cost whatever.
First source the components .I found 10 chips for sale for about $2 posted .
I found capacitors by the hundreds for $1 .
That's all you need . You can probably source the caps from old circuits or what you have in your junk box . I don't think they have to be too close to 100nf to do the job.
The output between the negative line ,pin 4 and the output wire ,pin 6 , is exactly 10.000 volts with pretty well any voltage fed in as a supply voltage between about 11 and 30 volts.
Solder a capacitor on to the negative pin ,pin 4 . Solder the other lead to pin 2 the positive pin.
Solder another capacitor pin to the negative pin ,pin 4 and solder its other lead to the output pin ,pin 6.
The chips pins are counted from the dimple on one end ,left of that looking at it is pin 1 through to 4 continuing on round the other side to pins 5 to 8 in an anticlockwise direction. See my marked diagram .
Thats it , don't bother with the resistors or switch on the right side of the diagram as thats only if you want to cut the output to 1.000 volts.
If you want to adjust your multimeter then Duck Duck "adjusting your multimeter for voltage"