Accidentally Technical

Knowledge, which is acquired under compulsion, obtains no hold on the mind.

[notetoself-technical]

Voltage exists independently; current is the consequence of giving voltage a path. Voltage enables danger, but current is what actually does damage.

[notetoself-technical]

Separation of field theory from circuit theory

Originally, in the 1800s, all electricity was studied in terms of fields in space—electric lines of force, magnetic flux, geometry of conductors, etc. That’s field theory, the space domain. But as technology developed (telegraphs, power systems, AC analysis), engineers realized that in most practical cases, the physical dimensions of a circuit are tiny compared to the wavelength of the signals moving through it. 

That meant the spatial variations of the fields could be ignored—the entire wire, capacitor, or coil could be treated as if everything inside it changes uniformly in time. So, instead of solving Maxwell’s partial differential equations in 3D space, they could replace those distributed effects by lumped parameters (R, L, C) and study how voltage and current vary only with time.

This was a deliberate abstraction—the birth of circuit theory. It’s not that geometry stopped mattering; it’s that it became embedded in constants like R=ρ*l/A and C=ε*A/d​. When frequencies get high (like in antennas or transmission lines), we go back to field theory—because then space can’t be ignored.

So that separation between space-domain physics (fields) and time-domain behavior (circuits) is one of the most elegant simplifications ever made in engineering—a kind of silent agreement:

“We’ll stop thinking in fields, for now, as long as the space is small and the time is slow.”

That’s how modern electrical engineering was born.

[notetoself-technical]

Fluorescent Light and Ballast Circuit

The fluorescent lamp functions on the principles of gas discharge and fluorescence. Inside the tube, low-pressure mercury vapor emits ultraviolet (UV) radiation when electrically excited. The inner surface of the tube is coated with a phosphor material, which absorbs the UV radiation and re-emits it as visible light. The lamp contains two heated electrodes (filaments) positioned at both ends of the tube to initiate and sustain the electrical discharge through the gas, as illustrated in Figure 1. 

Principle of Operation

When an AC voltage is applied to the fluorescent lamp, the filaments at both ends of the tube are heated, initiating thermionic emission, whereby electrons are released into the surrounding gas. These free electrons are accelerated by the applied electric field and collide with the low-pressure mercury vapor, causing ionization and rendering the gas partially conductive. As ionization increases, a stable current path, or arc discharge, is established between the electrodes, with the direction of electron flow reversing every half cycle due to the alternating nature of the supply. The collisions of high-energy electrons with mercury atoms result in the emission of ultraviolet (UV) photons (approximately 254 nm). These photons excite the phosphor coating on the inner surface of the glass tube, which subsequently re-emits the absorbed energy as visible light through the process of fluorescence. The specific phosphor composition determines the spectral characteristics of the emitted light, thereby defining the color of the lamp’s illumination.

Electrical Aspect

As the gas inside the fluorescent lamp becomes ionized, its electrical resistance drops sharply, requiring the ballast to limit current and prevent excessive current flow that could destroy the lamp or the power circuit. In addition, the starter and power supply provide the necessary ignition voltage and sustain the arc once the lamp is operating. 

The Ballast Circuit

The ballast power circuit at the steady-state operation is shown in Figure 2:

Figure 2. Simplified schematic of the electronic ballast circuit (adapted from Reatti, Alberto. “Low-cost high power-density electronic ballast for automotive HID lamp.” IEEE Transactions on Power Electronics, vol. 15, no. 2, 2002, pp. 361–368).

This circuit is a two-stage electronic ballast designed to supply a controlled AC current to a gas discharge lamp (with ignitron or starting circuit). Its main objective is to limit current and ensure proper ignition and steady operation of the lamp.

The design consists of three main sections:

1. High-frequency resonant inverter (100 kHz)

2. Rectifier and DC-link filter

3. Low-frequency inverter (400 Hz) feeding the lamp

Current-Limiting Mechanisms

In the ballast circuit, current regulation is primarily achieved through the combined effects of capacitive reactance, inductive reactance, and controlled switching of the inverter.

Capacitive Reactance of CC​: The coupling capacitor CC​ is connected in series with the lamp, presenting an opposition to changes in current according to its capacitive reactance​. CC​ blocks any DC component, preventing excessive bias or runaway current through the lamp.

Inductive Reactance of LI​: The inductor LI​ introduces inductive reactance, which opposes sudden changes in current by storing energy in its magnetic field. During each half cycle, LI​ smooths the current waveform and limits transient spikes that could occur during ignition or switching transitions. The interaction between LI​ and CC​ often establishes a series resonant condition, allowing efficient energy transfer at the desired frequency while naturally restricting overcurrent conditions outside the resonant band.

Controlled Switching of the Inverter: The inverter’s switching devices (M1​, M2​) operate at a controlled frequency and duty cycle to modulate the output voltage applied to the lamp circuit. By adjusting the timing and sequence of switching, the inverter effectively governs the power delivered to the lamp, thus ensuring that the current remains within the specified operating limits.

Conclusion

The operation of the fluorescent lamp illustrates the intricate interplay between fundamental physical phenomena and applied electrical engineering. While the underlying mechanism of light emission arises from gas discharge and fluorescence, the realization of stable and efficient operation is primarily attributed to circuit engineering. Through the precise configuration of resonant inverters, rectifiers, and ballast components, engineers ensure appropriate voltage and current regulation, thereby safeguarding the lamp against electrical instabilities and enhancing its operational longevity.

In this context, the ballast circuit assumes a pivotal role, as it embodies the principles of resonance, impedance control, and dynamic regulation essential for sustained illumination. It serves as a clear demonstration of how theoretical knowledge of electromagnetism and circuit behavior can be effectively translated into practical design. Consequently, the fluorescent lighting system represents not merely an application of physical laws but a refined engineering achievement that unites theoretical understanding with functional precision.

[notetoself-technical]

Capacity Factor

Definition

The capacity factor is the ratio between the actual energy produced over a certain period (usually a year) and the maximum possible energy it could have produced if it ran at full power 24/7.

Capacity Factor = Rated Power × Time / Actual Energy Output​

Capacity factor is less about the “brand” of your panel, and more about how much nature + design allow you to convert into real output. It’s a measure of potential utilization, not just the panel quality.

Example

Suppose you build a 10 MW solar PV plant:

Theoretical maximum (if it worked 24/7): 10 MW × 8760 hours/year = 87,600  MWh/year.

Actual yearly generation (from measurements): 19,000 MWh/year.

CF=19,000 / 87,600 ≈ 21.7%

So, you can advertise a 10 MW plant, but in reality it “behaves” like a 2.2 MW plant averaged over the year.

Subtle but important points

Not about instantaneous power

CF doesn’t mean your 100 kW system is only producing 20 kW at a time.

It means over the year, it delivered the energy equivalent to running at 20 kW all the time.

Location ≠ the only factor

Location dominates, yes (solar irradiation, climate).

But system design (orientation, tilt, cleaning, maintenance, inverter efficiency) also matters.

A dirty, shaded, or badly oriented array in Algeria could have a lower CF than a clean, optimized one in Spain.

Investment implications

When you design a solar business plan, CF directly affects payback.

Example: Two identical 1 MW farms, one with CF = 20% and another CF = 30% → the second one produces 50% more yearly energy for the same capital cost.

[notetoself-technical]

Parmenides, Einstein, and Popper: Reality, Change, and the Block Universe

Parmenides, the early pre-Socratic philosopher, held that reality (being) is single, continuous, undifferentiated, and eternally the same. Change, becoming, multiplicity—these he regarded as illusions, mere appearances. Reality, properly understood, is unmoving, ungenerated, indestructible, and simply is, always.

Einstein’s theory of relativity—in particular the idea of a four-dimensional spacetime, or “block universe” (where time is another dimension analogous to space, and all events—past, present, and future—are equally existent within this four-dimensional manifold); reignited debates about whether change is real or whether the flow of time is only apparent.

Karl Popper drew a sharp connection between Einstein’s block universe and Parmenides’ ancient doctrines. Popper saw Einstein’s conception as, in one sense, a modern scientific formulation of what Parmenides had already claimed. But Popper also challenged this conception, because he believed that reality includes genuine change, succession, and an “open” future: not everything is laid down eternally and statically.

Popper is often attributed with the quote:

“I have spoken to Einstein, and he admitted to me that his theory was in fact no different from the one of Parmenides.”

In his autobiography Unended Quest: An Intellectual Autobiography, Popper elaborates:

“The main topic of our conversation was indeterminism. I tried to persuade him to give up his determinism, which amounted to the view that the world was a four-dimensional Parmenidean block universe in which change was a human illusion, or very nearly so. (He agreed that this had been his view, and while discussing it I called him ‘Parmenides.’)”

So, Popper reports that Einstein, at least in private conversation, acknowledged that there is a sense in which his relativistic spacetime picture accords with Parmenides: change, in the deepest sense, is illusory or secondary; what truly is resides in a timeless four-dimensional totality.

Analysis: Where Popper Agrees and Where He Pushes Back

I. Agreement with Parmenides (through Einstein’s theory):

The block universe concept: Einstein’s relativity, especially in its spacetime formulation, supports a view in which all moments—past, present, and future—have equal reality. This is structurally similar to Parmenides’ view: reality does not truly change; rather, what we call change or becoming is a way of seeing parts of the unchanging whole.

Determinism or near-determinism: In a “block universe” everything is laid out; if everything (including future events) already belongs in the 4D manifold, then change in the sense of coming-into-being or passing-away may lose its ontological grip. Popper represents Einstein as accepting that his theory “amounted to the view that the world was a four-dimensional Parmenidean block universe.”

II. Popper’s criticism and insistence on an “open universe”:

For Popper, the problem with a strict block universe is that it seems to eliminate real change, succession, and especially novelty—things like free actions, moral responsibility, or future indeterminacy. Popper was strongly in favor of indeterminism: the idea that the future is not fully determined by the past and present. He believed in real temporal becoming—that events are not just in the block but unfold in time in a way that matters.

Popper argues that even though theories like Einstein’s might suggest a Parmenidean view, one should not give up “common sense” entirely with respect to time and change. He sees a philosophical need to defend the reality of succession and the openness of the future.

Implications and Tensions

The tension between common human experience (we feel change, the past changes into the future, things come into being, time flows) and theoretical physics/metaphysics (which at least in some readings suggests a block universe). Popper places importance on not allowing theoretical elegance to sweep away what seems fundamentally real.

If change is illusion, what becomes of ethics, freedom, creativity? Popper thinks these demand that the future is genuinely open, not just “laid out” in a static structure.

Philosophically, Popper treats Parmenides not as an enemy but as a kind of ancestor: a thinker whose radical insight forces us to think deeply about being, but whose conclusions need critical dialogue. Parmenides helps frame critical questions, but Popper does not accept all of Parmenides’ conclusions unmodified.

Conclusion

To sum up: Popper saw in Einstein’s block universe a close echo of Parmenides’ thesis that reality is unchanging and eternal. Einstein—at least in conversation—acknowledged the similarity. But Popper did not accept that as the final word. He defended an indeterministic, temporal, dynamic view of the world, in which change, novelty, and the open future are not illusions but part of what it means for things to be real. In his view, philosophy must neither shy away from the demands of physics nor capitulate to any view that denies the lived reality of time and change.

[notetoself-technical]

Heuristic Algorithms

Heuristic functions are intuitive guiding estimates that are commonly applied to search and iterative algorithms, assisting in determining which paths or approximations are more strategic. Search algorithms focus on exploring paths and consequences of actions to guarantee exact solutions, rather than the end result as in iterative algorithms.

Search algorithms are found in applications such as GPS navigating systems (used to find the shortest or fastest route) and in puzzle solving and games (searching through possible moves). Meanwhile, iterative algorithms are found in applications such as optimization problems (used to gradually improve a solution, like tuning parameters in machine learning) and in engineering design (refining models step by step to reach better performance).

Heuristics in search algorithms

A* is a best-first search algorithm that tries to find the shortest path to a goal through the use of heuristics. The heuristic function h(n) is the “extra knowledge” that guides A* toward the goal more efficiently than just exploring blindly as in simple search algorithms (e.g., brute-force search, depth-first search, etc.).

A* decides which node to expand based on a scoring function f(n):

f(n) = g(n) + h(n)

g(n): the cost from the start node to the current node n. It grounds the direction decided by h(n), ensuring no “rushing” toward the goal along an expensive path.

h(n): the heuristic function, an estimate of the cost from n to the goal. It gives direction and biases the search toward nodes that appear closer to the goal.

f(n): the total estimated cost of the path going through n.

Example: If you’re searching for a route on a map:

g(n) = the actual distance traveled so far.

h(n) = straight-line (as "the crow flies") distance to the destination.

A* will pick the next step based on the node with the lowest f(n).

Heuristics in iterative algorithms 

Simulated annealing is an iterative improvement algorithm, which doesn’t guide the direction directly; instead, the heuristic is used to compare solutions and decide if a move is accepted. 

In annealing If the new solution is better, we accept it (the heuristic decides that “this improves quality”). If the new solution is worse, it might still accept it with some probability.

Example: P=e^(−ΔE/TP)

ΔE = how much worse it is (difference in heuristic values).

T = temperature (a control parameter that decreases over time).

This mechanism avoids getting stuck in local optima by allowing a worse step, hoping to escape a dead end.

Heuristics serve as powerful guiding tools in both search and iterative algorithms, but their roles differ in purpose and application. In search algorithms, heuristics estimate the proximity to the goal, combining with actual path costs to efficiently find exact solutions, as seen in A*. In iterative algorithms like simulated annealing, heuristics act as evaluators of solution quality, supporting exploration by occasionally accepting worse solutions to avoid local traps and reach near-optimal outcomes. Together, these approaches highlight how heuristics transform problem-solving—from precise pathfinding to adaptive optimization—making them fundamental across diverse real-world applications. 

[notetoself-technical]

Time Complexity

Exponential time, logarithmic time, and quadratic time, etc., are such malevolent terms that they conceive horror, caution, and curiosity. However, time is an extension of violation only as a computer performance metric—known as time complexity.

The speed of an algorithm is calculated using the concept of time complexity, which measures the development of steps or actions in accord to that of inputs supplied; this signifies the amount of time an algorithm requires to terminate tasks, making time complexity crucial in algorithm/model selection, especially as the input variables grow.

The time complexity of algorithms is commonly described using Big O notation (e.g., O(1), O(n), O(log n), O(n²)). Big O expresses how the runtime grows with input size, usually focusing on the worst-case scenario.

[notetoself-technical]

Solar Battery Definition I

A solar battery is designed to charge from the PV panel or the grid, according to the system configuration, to ensure the system's autonomy during nighttime or periods of low sun radiation. The autonomy of a system is expressed in a number of days, and it depends on the location of the installation on planet Earth—sunny regions require less autonomy, while cloudy regions demand more. Therefore, larger battery banks are typically found in regions with low solar exposure. 

A solar cell is mainly defined by: 

The DC system operation voltage in volts, usually 12 V or 24 V.

Its Capacity, expressed in ampere-hours, which indicates the amount of current it can supply over time.

The stored energy, calculated as Voltage x Capacity (V x Ah), measured in watt-hours.

[notetoself-technical]

Solar Cell Working Principles

A semiconductor solar cell is essentially a large p-n junction, operating according to the same principles regardless of its material type through three steps:

Charge carrier generation: Incident sunlight is absorbed by the semiconductor, exciting electrons from the valence band to the conduction band and creating electron-hole pairs.

Charge carrier separation: The built-in electric field at the p-n junction drives the separation of electrons and holes: holes are pushed toward the p-type, and the electrons are pushed toward the n-type. The separation minimizes recombination of the charge carriers, allowing their movement.

Transport and collection of charge carriers: The separated electrons flow through the external circuit toward the p-type side, delivering usable electrical energy, while holes move internally toward the p-type contact. At the p-type contact, electrons recombine with holes, completing the circuit.

The figure below illustrates the cycle of generation and separation of electron-hole pairs in a PN junction under illumination.

[notetoself-technical]

On solar energy in Algeria

Academics ridicule solar energy and any form of renewable energy, for it is a fantasy or something humorous due to how "impractical" it is, at least in my experience as a power engineering student. I have heard professors acclaim the impossibility of electric production in PV installations given the smallest inconveniences, such as the afternoons and early mornings, rise in temperature, or some shadows, attributing it to the intermittency of the weather and fragility of the solar cell technology. This demeanor has pushed Academics ridicule solar energy and any form of renewable energy, for it is a fantasy or something humorous due to how "impractical" it is, at least in my experience as a power engineering student. I have heard professors acclaim the impossibility of electric production in PV installations given the smallest inconveniences, such as the afternoons and early mornings, rise in temperature, or some shadows, attributing it to the intermittency of the weather and fragility of the solar cell technology. This demeanor has pushed students, the ones with technical knowledge and ability to enhance the field, to disdain renewable energies. And because the field is known for its initial high cost, it is dominated by businessmen in Algeria who can't even dream of identifying the direction of the electric current, resulting in installations without respected norms and unnecessary added cost to their clients, further slandering renewable energies and discouraging people from integrating green solutions.

What is important to highlight is that renewable energies are alternative energies; they cannot compete with gas or vapor turbines. However, pairing renewable energies with conventional energies offers the best solution for meeting global energy demands because it combines the strengths of both systems while minimizing their weaknesses. Additionally, the claim that PV systems are weak is incorrect; a PV panel can generate energy even when faced behind the sun or with its face on the ground, and the only way it outputs 0 voltage is when it is placed in a room with no light and nothing can be seen. As long as we are alive, there's the sun; hence, there's surely PV production. The potential and science of solar energy belong to engineers. of both systems while minimizing their weaknesses. Additionally, the claim that PV systems are weak is incorrect; a PV panel can generate energy even when faced behind the sun or with its face on the ground, and the only way it outputs 0 voltage is when it is placed in a room with no light and nothing can be seen. As long as we are alive, there's the sun; hence, there's surely PV production. The potential and science of solar energy belong to engineers. , the ones with technical knowledge and ability to enhance the field, to disdain renewable energies. And because the field is known for its initial high cost, it is dominated by businessmen in Algeria who can't even dream of identifying the direction of the electric current, resulting in installations without respected norms and unnecessary added cost to their clients, further slandering renewable energies and discouraging people from integrating green solutions.

[notetoself-technical]

Voltaic pile battery

Alessandro Volta is the inventor of the voltaic cell, or voltaic pile, which is one of the early batteries capable of generating continuous current. A single cell is constructed using a copper disc, followed by a fabric soaked in an electrolyte solution, and then a zinc disc, all stacked on top of each other. In Volta's experiment, he arranged multiple cells in a stack, with a conductor connecting the top and bottom discs, thus completing the circuit and allowing for the flow of electric current.

In addition, Volta's invention also played a significant role in advancing our understanding of EMF (electromotive force). Through empirical observation, Volta recognized that the flow of current in the battery was driven by a force he termed 'EMF.' This insight marked a crucial distinction between electrostatic electricity and the continuous current generated by batteries, whether it be AC (alternating current) or DC (direct current). This distinction ultimately contributed to the development of electrical generation and the early comprehension of electricity.