Standard Resistor Values

[EWBrown]

The best "modern" application for small 1/2 or 1/4 watt CC resistors is to use them as grid stoppers, the actual resistance value isn't critical, as virtually no current flows through them. The grid stopper just serves as a simple RF and spurious oscillation preventer, using the miller effect and interelectrode capacitance of the tube as the "C" portion of a very simple RC filter. Any value from 100 to 10000 ohms is fine, I generally use 220 or 330 ohms, and 1K, 1/4 watt, 5 or 10%, only because I have a lot of those values.

Old CC resistors can, and, do drift in value, sometimes far out of their original specs. The composition can absorb humidity, salt air vapor, etc, as the phenolic resistor body isn't all too well hermetically sealed, and the points where the wires enter the resistor body aren''t all that solid, and the leads can get corrosion inside at the point of contact with the internal resistive composition mix. Just like old electrolytics, paper caps, etc, CC resistors aren't "immortal", even just sitting, unused, in storage - which is usually located in some damp and musty cellar, barn, shed or warehouse for decades and generations :o


/ed B in NH