:A month ago, I bought a used Radio Shack 20-Range Auto Ranging Digital Meter (Catalog # 22-806) - but when I went to use it recently, the "new" batteries were completely dead. I replaced the batteries again and it worked - but on a hunch, I put another meter across the battery terminals (with the batteries out) and got a reading of around 350 ohms! It is one of those with an electronic switch that shuts itself off after 30 minutes. I couldn't locate the schematic online - but after disassembly, I noticed a SMD capacitor mounted between the battery terminals. On another hunch, I removed that cap and the resistance dropped below 0.4 Mohm and the meter still works - so, it appears the cap was shorted. What is the purpose of that cap and will it be okay to leave it out or should I replace it? If I do need to replace it, what value should I use? I have had this same thing happen in a remote and a shower radio - I left the caps out of both of these and they still work after many years.... Thanks
The cap across the battery is to keep the meter working when the internal resistance of the battery increases due to age. Actually, it does not do very much with a new battery, and as the battery ages it just provides a AC ground. You probably will not find much difference with or without it.
Lewis