My recommendation is: Get an easy to read textbook that contains four sections: DC electronics, AC electronics, semiconductors, and electronic circuits.
DC (Direct Current) Electronics: The DC module should lay down a basic foundation upon which to build your knowledge. You must learn what Direct Current (DC) is. Then you should be taught about voltage, current, and resistance. You must learn about the DC electronic components called resistors, about switches, the ground and batteries, and what they are used for and know what their schematic symbols look like.
You need to learn Ohms Law, as it is invaluable in assisting you in calculating current, voltage, resistance and power. You need to learn basic DC series and parallel circuits. You must learn voltage drops in DC circuits. The student must learn what a short and and an open is and how voltage and current is impacted in a circuit. The student must be taught how to visualize how an open impacts a circuit and each component in a circuit. Use of Ohms Law should be used to help the student know or predict how circuit or a component in that circuit will react in the case of an open or a short. You must learn how to calculate voltage, current, and resistance in a circuit. You need to learn who to determine the value of a resistor when given the resistance color code chart. You should learn how to use an electronic calculator. (A simple one.)
The student should then be introduced to the multimeter, which is a tool that allows one to measure current, voltage, and resistance in electronic circuits. It also allows for out of circuit tests of electronic components. The student should be taught how to use this tool. The student should be taught how to use the multimeter to determine if a resistor, switch, or fuse is bad (open or short).
Once you have laid a solid foundation in DC electronics and have a through understanding of it and the components in a DC circuit, now you can build upon that and move on to AC Electronics.
AC (Alternating Current) Electronics: The AC Electronic module should - at first with discussion - explain to the student the difference between AC and DC. The student should be shown what Alternating Current is, shown what an AC wave looks like compared to Direct Current, and why and when AC is used. Then the student should learn about AC electronic components such as the capacitor, insulator (coils) and generators, and know what their schematic symbols look like and what they do in AC circuits.
The student should be taught capacitance, inductance, reactance (inductive and capacitive), frequency and time. The student should learn what capactive and inductive reactance are and know how to calculate them. The student should be taught how DC effects and AC component - such as a capacitor - and how an AC component effects a DC component such as a resistor. These visualizations and skills are important when reading circuit diagrams.
The student should be introduced to the oscillator and signal generators which are used in measuring and troubleshooting AC circuits (and DC circuits if necessary). Once it is clear to the student how AC circuits work, then they can move on to semiconductors.
Semiconductors: These are diodes, zener diodes, transistors and IC chips and the student should know what their schematic symbols look like. It is extremely important that the student understand the basic atomic structure that make up these components (Silicon and Germanium), as this will assist them in knowing what to expect as far as voltage drops across them.
The student should be told what diodes are and what they are used for in Electronics circuits, showed in turn a diode in a simple series DC circuit consisting of a DC voltage source and a resistor and how diodes are "biased" connected in a circuit. The student should have explained the difference between "forward" and "reverse" bias.
The student should be shown current flow in the circuit and how the DC voltage drops across each component in that circuit. The voltage drops across the resistor and diode should add up to the DC voltage source. The student should be shown what happens if the diode opens or shorts out in the circuit. This is extremely important to troubleshooting circuits and learning about transistors. The student should be taught how to quickly check to see if a diode is open or shorted using a multimeter.
The student should then be taught how diodes work in AC circuits and why and when they are used in AC circuits.
The student should be taught all about transistors. If the student has mastered diodes, then they should be taught to visualize a transistor as two diode connected back to back.
The student should learn about Zener diodes and what they are used for learn how they work in electronic circuits. The student should be taught how to quickly check for a bad Zener diode using a multimeter.
Students should learn the three basic transistor configurations and when they are used. The student should be taught exactly how transistors are biased (connected) to a DC source. The student must be taught why resistors MUST be connected in transistor circuits. The student should learn how DC current flows in through a transistor and in a transistor circuit. The student should be taught to "visualize" DC voltage drops in a transistor circuit. The student should be taught how to quickly check a transistor to see if it is open or shorted using a multimeter. If the student understood diodes, understanding how transistors work and testing them will be easy.
Next, the student should be taught that a transistor typically will have two currents running through them: DC and AC. They should be taught that transistors are first biased (connected) with a DC source and then AC is ran through them so that the transistor amplifies the AC signal.
The student can be taught to visualize DC bias of a transistor (or diode) as with starting a car, but the gas pedal is not depressed. The car is just idling (biased). When the gas pedal is pressed it is like AC being pumped through the transistor.
Once DC, AC and semiconductors are learned, then the student can move on to electronic circuits where we see all three operating together in more complex circuits.
Electronic circuits: Here the student will apply what he has learned about DC, AC and semiconductors. He will learn about amplifiers, oscillators and the many complex electronic circuits that have DC and AC in them.
The student should be taught to "see" and isolate (visualize) the DC and AC circuits within the much larger circuit. The student should be taught how one circuit is "coupled" or connected to another circuit and how to troubleshoot them using schematic diagrams.
Just master DC then move to AC. Master AC then move to semiconductors. Master semiconductors and then put them all together to study the many electronic circuits. You should have no problem.
It would be helpful to have a breadboard, electronic components, multimeter, signal generator and a DC source to build circuits.
Two recommended textbooks: "Basic Electronics" by Heathkit (hard to find); "Electronic Principles" by Albert Malvino, Sixth Edition (my personal favorite).
