A Simple, Valve Curve Plotter

[pwdrive]

Done a few calculations for a DC supply of 8 volts:


Series connected pot (rheostat)

Series R based on some typical minimum and maximum (ish) heater currents that might be commonly encountered, there will be some odd balls but I've left them out to keep things simple.

All calculated from a nominal 8 volt DC supply based on 6.3 volts AC in to the rectifier, the 8 volts out is just a guess....adjust as required

R = series resistance, Pd = dissipated power:

1.4 volt heater at 25 ma:
R = 264 ohms, Pd = .165 watts

1.4 volt heater at 250 ma:
R = 26.4 ohms, Pd = 1.65 watts

4 volt heater at 100 ma:
R = 40 ohms, Pd =.4 watts

4 volt heaters at 300 ma:
R = 13.3 ohms, Pd = 1.2 watts

4 volt heater at 500 ma:
R = 8 ohms, Pd = 2 watts

4 volt heater at 1 amp:
R = 4 ohms, Pd = 4 watts

6.3 volt heater at 100 ma:
R = 17 ohms, Pd = .17 watts

6.3 volt heater at 300 ma:
R = 5.66 ohms, Pd = .51 watts

6.3 volt heater at 500 ma:
R = 3.4 ohms, Pd = .85 watts

6.3 volt heater at 1 amp:
R = 1.7 ohms, Pd = 1.7 watts

Someone else can work out for 5 volt heaters.

Any errors then guilty as charged

Lawrence.