BK Precision 2703C Design Quark  - Page 1
Forum section: electronics / testgear

author: LoveToRepair
author_rank: Newbie
timestamp: May 02, 2025, 03:00:18 am
content: I found out that My2703 Meter is set up in a way that in order to use the 1.5V Battery test mode. you have to insert the meter lead into the mA Jack. But the 9Volt mode is the standard VO Jack. What? Why not put the 1.5 Volt Batt test on the same jack as the 9 Volt mode?Would there be any logical reason to do this?

author: zepto
author_rank: Regular Contributor
timestamp: May 02, 2025, 03:20:08 am
content: it will load the battery and be a better gauge of health.

author: EEVblog
author_rank: Unknown
timestamp: May 02, 2025, 03:21:03 am
content: They must be switching the mA through the range switch, and using the 2mA mode that would likely have a 100 ohm shunt resistor.Usually it's 1 ohm shunt resistor for a 200mA range which would blow the fuse with any decent battery capable of a few hundred mA at least.

author: LoveToRepair
author_rank: Newbie
timestamp: May 02, 2025, 03:23:31 am
content: No I mean. Why make it so that I have to plug the lead into the mA Jack? Why wouldn't they have put the 1.5V Batt test mode in the Main Volt Ohm jack like the 9Volt Mode is?

author: EEVblog
author_rank: Unknown
timestamp: May 02, 2025, 03:26:48 am
content: Quote from: LoveToRepair on May 02, 2025, 03:23:31 amBecause they already had the 100ohm shunt resistor for the 2mA range, and they are using that as a load for the battery.You can measure this shunt resistance by using another meter in ohms mode.From a design point of view you could have done it with he range switch, but then for protection you would have needed another fuse to protect against oopsies on the 1.5V battery test mode.The 9V mode probably doesn't have any load on it, or maybe something high like 10k.When testing a battery it's best to have a load on it so that high ESR shows up a problem.

author: EEVblog
author_rank: Unknown
timestamp: May 02, 2025, 03:34:48 am
content: Quote from: LoveToRepair on May 02, 2025, 03:31:30 amYeah, my guess would be at least 10k, otherwise if you used say 1k which would otherwise be a usable test current of 9mA, if the user accidentally puts say 100V across the probes then the resistor will fry with 10W of dissipation.On second thought, better to use a PTC with a nominal value of 1k-2k cold.

author: LoveToRepair
author_rank: Newbie
timestamp: May 02, 2025, 03:35:49 am
content: yes that is why I like having meters that will put a load on the battery. I am just used to not having to put the Lead into the mA jack. I still hear Danger Danger Will Robinson in my head every time I put the lead in that jack to test 1.5V Batteries.

author: EEVblog
author_rank: Unknown
timestamp: May 02, 2025, 03:37:18 am
content: Quote from: LoveToRepair on May 02, 2025, 03:35:49 amYeah, that's kinda freaky. And then you end accidentally leaving the probes in there for next time when you try and measure voltage...

author: EEVblog
author_rank: Unknown
timestamp: May 02, 2025, 03:40:13 am
content: This Agilent had the battery charge input on the mA jack, and a signal gen output, that was freaky.

author: LoveToRepair
author_rank: Newbie
timestamp: May 02, 2025, 03:40:42 am
content: Yes That's exactly what I am afraid of. So I make it a point to switch the Probe Back to the Volt Ohm Jack. I think I might use My other Meters that load the Battery more often though. Just to be on the safe side. I really don't want to fry My BK meter

author: LoveToRepair
author_rank: Newbie
timestamp: May 02, 2025, 03:43:25 am
content: I swear they do things like this deliberately. Just to mess with all of us

author: EEVblog
author_rank: Unknown
timestamp: May 02, 2025, 04:19:35 am
content: Quote from: LoveToRepair on May 02, 2025, 03:43:25 amAnother load resistor and polyswitch would have been a better design option, but they saved a few cents.