---
# System prepended metadata

title: Electronic Circuits - Part 1

---

# Electronic Circuits - Part 1

:::info
Notes on [超圖解電子電路入門](https://www.books.com.tw/products/0010984558?gad_source=1&gclid=CjwKCAjwpbi4BhByEiwAMC8JnUPW47W86eFaA1116kWFjKRXyuPFPv6mbPZq7I88nCt4gTlgNMWDrBoCv7kQAvD_BwE)
:::

## Ohm's Law[^omelet]
[^omelet]: Omolet is good. ![](https://i2.wp.com/www.downshiftology.com/wp-content/uploads/2021/12/How-to-Make-an-Omelette-17.jpg =20%x)

[Georg Ohm](https://en.wikipedia.org/wiki/Georg_Ohm) 1789-1854

![](https://upload.wikimedia.org/wikipedia/commons/d/dc/Ohm3.gif =20%x)

$$
V = I * R
$$

`V`: Voltage (V, volts)
`I`: Current (amperes, amps)
`R`: Resistance (Ω[^ohm], ohms)
[^ohm]:  Type Ω by `option + z` on macbook


## Kirchhoff's Circuit Laws
[Gustav Kirchhoff](https://en.wikipedia.org/wiki/Gustav_Kirchhoff) 1824-1887

![](https://upload.wikimedia.org/wikipedia/commons/thumb/f/fe/Gustav_Robert_Kirchhoff.jpg/400px-Gustav_Robert_Kirchhoff.jpg =20%x)

- Kirchhoff's Current Law (KCL)
- Kirchhoff's Voltage Law (KVL)

![](https://as2.ftcdn.net/v2/jpg/04/98/66/87/1000_F_498668731_JbMhnjLDq9a56U2CByBrBb0UBEusizzh.jpg =80%x)

### Read more
- KVL https://spinningnumbers.org/a/kirchhoffs-voltage-law.html

## Power[^chainsaw_man]
[^chainsaw_man]: Her name is Power. She is ~~an angel~~ a demon. ![](https://i.imgur.com/1VjFpiZ.png)

[James Watt 1736-1819](https://en.wikipedia.org/wiki/James_Watt)
![](https://upload.wikimedia.org/wikipedia/commons/thumb/1/15/Watt_James_von_Breda.jpg/440px-Watt_James_von_Breda.jpg =20%x)

$$
P = V * I
$$

`P`: Power, measured in watts, the rate at which electrical energy is consumed or produced.
`V`: Voltage, measured in volts, the force pushing electrons through a circuit.
`I`: Current, measured in amperes, the flow rate, the number of electrons passing a point per second.


## Energy

[James Prescott Joule](https://en.wikipedia.org/wiki/James_Prescott_Joule) 1818-1889

![](https://upload.wikimedia.org/wikipedia/commons/0/0f/Joule_James_sitting.jpg =20%x)

$$
E = P * t
$$

`E`: Energy, measured in joules
`P`: Power, measured in watts
`t`: time in seconds

- Run a 60W light bulb for 2 hours. $Joules = 60W * (2 * 3600s) = 432,000$

## Analogy of Sisyphus
Sisyphus was condemned by the god to endlessly roll a boulder up to hill, only to have it roll back down each time he neared the top. [^atlas]

![](https://i.imgur.com/wfY8msi.png =300x)

[^atlas]: How cruel God can be! Atlas was also condemned to hold up the celestial spheres on his shoulders. "Atlas Shrugged" is the title of a novel by Ayn Rand. ![](https://upload.wikimedia.org/wikipedia/commons/8/8c/MAN_Atlante_fronte_1040572.JPG =200x)

- Voltage (V, volts) is like the strength of Sisyphus.
- Resistance (R, Ω) is like the steepness of the slope.
- Current (I, amps) is like the size of the boulder.
- Power (W, watts) is like the rate at which Sisyphus is doing work.
- Energy (J, joules) is like the total work Sisyphus does over a period of time.


## Hertz
[Heinrich Hertz](https://en.wikipedia.org/wiki/Heinrich_Hertz) 1857-1894

![](https://upload.wikimedia.org/wikipedia/commons/5/50/Heinrich_Rudolf_Hertz.jpg =20%x)

$$
f = 1/T
$$
`f`: a unit of frequency
`T`: period in seconds


- 10 Hz equals 10 "cycle" per second. 
- A cycle includes a complete positive half and a complete negative half.

```
   |    /\
   |   /  \
---+--/----\--/\---
   | /      \/  \
   |/            \
   |              \
   |
   +---------------->
      |1 cycle |
```
- AC power[^ac]: Completes 50 or 60 cycles per second (Taiwan is 60 Hz).

[^ac]: 交流電 (Alternating Current, AC)

![](https://www.djtelectricaltraining.co.uk/images/images/guides/Frequency/50Hz-frequency.jpg =70%x)

### The whale

The 52-Hz whale, the loneliest whale in the world, calls at an unusually high frequency of 52 Hz.

- [The Sound](https://soundcloud.com/bbc_com/the-52hz-whale-recorded-by-bill-watkins) 
- [世上最孤獨的鯨魚「52赫茲」，你還獨自在唱寂寞的歌嗎？](https://pansci.asia/archives/112793)
