David McGown wrote:

Ohm's law is the most important thing to know when fiddling around with electronics. It is the basic equation for setting bias, for determining voltage drop across a resistor (such as a cathode or plate resistor, or a resistor/choke in a power supply). Anything dealing with DC parameters of a circuit. Know it, it is your friend.

Power law is the other important equation, P = VI (Power (Watts) = Voltage x current). This will let you know how much power you are dissipating across a resistor, tube, etc. Very important for selecting components such a resistors (always select a resistor rated approximately 2 times or more higher that the power dissipation) and for knowing how much you can push that output tube to keep within rated plate dissipation.

Master these equations, and you can deal with 90% of all tube circuit and power supply related design, bias and component selection.

David

My most important law when dealing with electronics is don't let your body complete the circuit. Ohm's law is right behind that. This wheel helps explain.

Tom