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I don;t know how well this will come out, but I scanned this little cardboard slide rule. Print out the page, cut out the slider, and cut out the black windows in the cover. The scales on the slider should fill the windows.
I'd print it on some heavy stock, and the cover could be bent around the top and bottom edges to form a guide.
I use this thing all the time. I find it faster and easier than my calculator. Especially if I am moving the numbers.
I mainly use it for working with speaker loads.
Set the load impedance at the OHMS arrow in the middle. Then you can read the scales where they line up. For example, if you have 8 ohms, and 25v across it, that translates to not quite 80 watts, shown in the top scale. Or maybe you wonder how much current flows when you have 70 watts. Not quite 3 amps, as shown in the lower window. You can even determine how large a resistor to use if you know the current flowing and know the voltage drop you want. For instance, say I have 8ma - like a couple of 12AX7s - of B+ and want to drop 30v. Skide says about 3800 ohms. The real answer is 3750, but close enough since the closest standard value resistor is 3900 ohms anyway.
Will it give you three decimal places? Of course not, but it is great for ball parking it.
Hey, maybe you will find it useful or interesting. And if not, well you are only out a sheet of stiff paper.
I'd print it on some heavy stock, and the cover could be bent around the top and bottom edges to form a guide.
I use this thing all the time. I find it faster and easier than my calculator. Especially if I am moving the numbers.
I mainly use it for working with speaker loads.
Set the load impedance at the OHMS arrow in the middle. Then you can read the scales where they line up. For example, if you have 8 ohms, and 25v across it, that translates to not quite 80 watts, shown in the top scale. Or maybe you wonder how much current flows when you have 70 watts. Not quite 3 amps, as shown in the lower window. You can even determine how large a resistor to use if you know the current flowing and know the voltage drop you want. For instance, say I have 8ma - like a couple of 12AX7s - of B+ and want to drop 30v. Skide says about 3800 ohms. The real answer is 3750, but close enough since the closest standard value resistor is 3900 ohms anyway.
Will it give you three decimal places? Of course not, but it is great for ball parking it.
Hey, maybe you will find it useful or interesting. And if not, well you are only out a sheet of stiff paper.
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