## Learning the Art of Electronics, Week 2

[latexpage]  2L1.1 Ok, I  form a simple low pass filter using unknown RC values. Then I measure time constant using scope and 500Hz square wave. Time constant is a time it takes for a voltage to reach ~63% of its total value. Measured time constant using RIGOL DS1054z is 0.268ms ( measured using manual cursors: I set Percent for Vert. Units, then Set range of the wave with vertical cursors and then measure time to rise to ~63% (bx-by) ) Measured time constant using Tektronix 2221A is 0.270ms ( I position the wave from 0 to 100% and then using cursors get ▲T for ▲V to reach 63.2% ) t = RC Now I need to find R. And task is to measure R without removing C. We can do that by imagining that RC is just R, but we have to eliminate XC. We can do that by increasing frequency unti we get no phase shift. The higher the frequency the less XC there is. We can see that XC is not effective anymore when we see no more phase shift. I add a known 1K resistor in front of RC filter. Apply sine wave and increase frequency…

## Learning the Art of Electronics, Week 1

Week 1. Ohms law, power, Kirchhoff`s law V,I. Ohm`s law V=IR. So what is a Volt ? Potential energy per unit charge or work done to move a charge against electric field, form one potential to a higher potential. Dynamic resistance Rdynamic= ΔV/ΔI it is the local resistance - the tangent to the slope of the device V-I curve. Power P=I×V or derived: P=I²R or P=V²/R Kirchhoff`s law: sum of voltages around circuit is zero, sum of currents in and out of node is zero. Parallel resistance: Rtotal = (R1×R2)/(R1+R2) Rule of thumb: if two parallel resistors differ by a factor of ten or more, then we can ignore the larger of two. In other words: in a parallel circuit, resistor much smaller than other dominates. Ina series circuits, the larger resistor dominates. Voltage divider. Rely on fact the I is the same on top and bottom. Vout = Vin × R2 / (R1+R2) Tip: since the current at the top and bottom are equal, the voltage drops are proportional to the resistances. So if the lower leg is ten times the upper leg, it will show 90% of the input voltage ( or 10/11 if exactly). Or if…

## Learning the Art Of Electronics

I have decided to get my self together and systematize my knowledge of electronics. It is very similar situation as for this guy. Electronics is my hobby. And actually one of many hobbies. I would say I have a lot of knowledge it but there are plenty of gaps and places just for intuition. Especially in circuit design. Once I have purchased a book "Learning The art Of Electronics" and used it as reference for this and that but never when through it. But this is it. My goal is to complete one lab at least once a week and post a report here. Hopefully I will make it through :)

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