My 40 year old Simpson 260 (at least that old) finally had the 30v battery head to zero volts. Used for the ohmmeter function. Love my Simpson. Have a half dozen digital ones around, but not the same as the big analog meter! Well, it was off to find a replacement battery. Dang hard to find a 30V battery but Interstate had them on line, so bought one. By the time it gets here with tax and shipping it will be $16. I guess that isn't too bad for 40 years. I remember when lots of things had "B" batteries. In the 50s, someone gave me a battery powered tube portable radio. I fixed it, and it took two C cells for the filaments and a 67v B battery. Wasn't cheap even back then, but the B battery lasted a long time. The C batteries lasted maybe 10 hours? It also had a cord to plug it in, so that is how it got used most of the time! I remember 'portable' ham equipment then used tubes - Pop tronics projects had lots of 'portable things' powered by B batteries. Now you struggle to find one. Of course, in the 1920s, when radio started , everything was battery powered. A 201 tube (took about 5v at an amp!)....the 201A took a lot less. They got tubes down to about 10ma of filament current before they left consumer products. I remember my first 'transistor project'. A CPO using a CK722 transistor that cost over a buck back in 1960 or so. Ran off a 1.5v bettery I think. Germanium PNP one, I think. Then it quickly went to silicon transistors and lower prices. Some 'transistor radios' ran on 9v batteries. They are still ubiquitous today for smoke detectors and loads of things. In fact, if you build some of the one tube radios (regens) they run off a few 9v batteirs in series to provide the B+. Maybe 27v on your regen radio. And, of course, a filament battery. I built up a 1 tube radio back in the 60s for a science project. I think it was a 3A5 tube - regen detector and audio amp. Would drive a tiny speaker on a very loud BC signal easy. I also built a crystal set hooked to a 100 foot antenna. If you listened close to a speaker, you could hear it....good nighttime radio...but it wasn't really selective enough to separate out completely the multiple loud stations, so you heard one louder, but the others mixed in. Loved Sunday nights when most of them went off the air after midnight for maintenence. Could do some good BC band DXing! (I was an SWL before I got my ham ticket in 1963.). Then I got fancy and got a Knight Kit Span Master and SWLed for another year or two.....then got ham license, and that was the end to BC band DXing and SWL listening. Heck, I even had a Pop Tronics SWL number WPE 2BLV? ..I forget what.... something like that. So how many people here remember B batteries? (and C batteries going back even further?). Or build xtal sets and regens, and did SWLing and BC band Dxing? Or own a Simpson 260 meter?