09-03-2019, 10:46 PM
OK, people, I looked at the data sheets for the tubes involved. The heater current is supposed to be 0.15amps. That is the current that should be running through this series circuit. Each of the 40 ohm resistors will dissipate 0.9 watts! That means that 3 watt resistors will work OK, being more than 3 times the wattage they will dissipate, 5 watt will be way more than sufficient, and 10 watt would be major overkill. Actually, the one with the bulb across it will dissipate even less because the bulb will be dissipating a lot of it. So, as I said in the beginning, 3 40 ohm, 3 watt resistors on a terminal strip should work fine.