Month: March 2021
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Waiting for my vaccine call. I shall not miss their call. Got my vaccination appointment.
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The best part of the best ANC is to enable you to enjoy the music at its 10% volume in a noisy environment. Especially the bass.
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In order to etch my own printed circuit board, I bought some ferric chloride. The seller instruction is to dissolve 40g in 110.5ml of water. To concoct 1 molar solution of FeCl3, according to its molecular weight, one will need 162.2g for every 1L of water. So with 100ml, 16.22g is needed. 40/110.5*100/16.22 = 2.232mol.
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Rem W is the diameter of the wire in mmRem W = 0.35Input “Diameter of wire in mm”,W Rem H is the diameter of the hole in mmRem H = 8Input “Diameter of hole in mm”,H Input “Length per winding in mm”,L Print “Winding calculator by Dr Liew”Print “March 7th, 2021”Print Print “Diameter of wire…
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A ferrite core is prefered. A metal nut doesn’t really work. Magnetic property is just not the same. More turns equal more Henry value of the coil. But given the size of the hole, how to calculate roughly how many times a wire of given size can pass through it? So first, we need to…
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Here is testing a Joule Thief circuit with a simple oscilloscope. It can bring the voltage of a battery (with as low as 0.3V left) high enough to light up an LED.
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Switching the AA battery with a D-cell. I have changed one of the 100nF ceramic capacitor to a 10nF version. Thus the frequency is now 10Hz instead of 1Hz. So, it can still blink for 10 years. This Energizer Max D-cell has a shelf life of 10 years. Need to find a housing for it.…