06-10-2017, 01:04 PM
It's also well worth while putting a couple of series-connected 1N5402 diodes across the LT supply. If you short HT to filaments, these'll clamp the voltage to 1.5V or so. Which is above the operating voltage, but not so much as to fuse them instantly.
I'm using a load of CR2032 cells from Poundland. With a drain of a few mA, I haven't had any issues yet. You can get holders from eBay sellers.
Then you really can work with power on. (But I do have a little on/off slide switch. which breaks LT AND HT).
I'm using a load of CR2032 cells from Poundland. With a drain of a few mA, I haven't had any issues yet. You can get holders from eBay sellers.
Then you really can work with power on. (But I do have a little on/off slide switch. which breaks LT AND HT).
