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trobbins · 11th Jul 2021, 1:50 pm

I just set up a 317L for 10mA to about -0.015% based on two 6 digit DMMs I have. Very simple finger heating of just the 317L lowered the output level, but similarly the same heating of the setting resistors raised the output level by about the same amount (about 0.0005mA either way). That's pretty reassuring given the room is about 15C and the datasheet shows a minor but consistent fall in reference voltage above about 15C.

I'll set up a 317T for 100mA tomorrow, as well as check for operation in to an inductive load (eg. when measuring the DCR of a transformer winding), as that scenario could well require a flyback diode for protection.

11th Jul 2021, 1:50 pm	#22
trobbins Heptode Join Date: Oct 2009 Location: Melbourne Australia Posts: 901	Re: Simple Low Resistance Measurement I just set up a 317L for 10mA to about -0.015% based on two 6 digit DMMs I have. Very simple finger heating of just the 317L lowered the output level, but similarly the same heating of the setting resistors raised the output level by about the same amount (about 0.0005mA either way). That's pretty reassuring given the room is about 15C and the datasheet shows a minor but consistent fall in reference voltage above about 15C. I'll set up a 317T for 100mA tomorrow, as well as check for operation in to an inductive load (eg. when measuring the DCR of a transformer winding), as that scenario could well require a flyback diode for protection.