Electronics - Sources and Studies

Datasheets

BJT Transistor
Darlington Transistor
PhotoTransistor
Displays

Study

Useful Channels

  • BenEater .

    • Very good. Talks about many subjects, always showing practical applications on breadboards.

  • ElectronXLab .

    • More in-depth explanations about Transistors.

  • PaulMcWhorter .

    • Good explanations of Arduino. He likes to complicate things tremendously, only to return to an extremely trivial subject; lacks common sense.

  • EngineeringMindset .

    • The explanations are very monotonous and shallow, but aimed at the general public, without going into depth.

  • RealPars .

    • Despite talking about more in-depth subjects, the explanations are shallow and monotonous, basically 'corporate'.

  • Explorer .

    • Great depth and with good visualization, but lacks a didactic explanation.

  • Book: The Art of Electronics Ed.3 .

    • Stopped on page 49.

Videos to watch

  • Thevenin's Theorem:

  • Using Transistors as Switch + BJT Playlist:

    • https://www.youtube.com/watch?v=s7k6Cmk731c&list=PL4651816D92AB6B2B&index=6.

  • Using Darlingtons as Switch:

    • https://www.youtube.com/watch?v=BpQD7m7VR8A.

  • Operational Amplifiers + Playlist:

    • https://www.youtube.com/watch?v=icFo5Zeydqg&list=PL1A9A9DCD87C218DB.

  • Common-Emitter Amplifier:

    • https://www.youtube.com/watch?v=9325TKD4dfY.

  • Explanation of MOSFETs .

  • Other circuit components from the ElectronXLab channel: https://www.youtube.com/@ElectronXLab/playlists?view=50&sort=dd&shelf_id=1.

  • Explanation of Batteries:

    • https://www.youtube.com/watch?v=PXNKkcB0pI4.

    • https://www.youtube.com/watch?v=VxMM4g2Sk8U.

Questions

About Beta (Hfe), 'V_BE Voltage Drop', 'V_CE Voltage Drop' and Saturation'

  • What defines the 'V_BE Voltage Drop'? How does V_BE vary? Does the graph represent its behavior?

    • <excalidraw_not_loaded>

  • What defines what the 'Saturation Voltage' is?

    • It is defined based on the moment when the V_CE Voltage is zero, causing the Transistor to act as a Switch.

  • What defines the 'V_CE Voltage' drop?

  • How can I give "less or more "voltage drop"" to the Base -> Emitter? Is it changed by varying I_B?

  • What defines the value of Beta (Hfe)?

  • Why does the value of Beta (Hfe) change with temperature?

  • Need to do the Voltage variation, in the first case.

    • <excalidraw_not_loaded>
About Amplification

  • What are the possible constructions for 'current amplification'?

  • 'Common Emitter' vs 'Common Collector' vs 'Common Base (?)'?

  • First Order RC Filter; passive filter.

  • Operational Amplifier?

  • 'Common Emitter' and 'Class A' are the same thing? Or does one derive from the other?

Ohm's Law

Voltage
Current
Resistance

  • Measured in Ohms.

Explanations I made for Paola

  • They contain a good analogy to the functioning of Current and Resistance.

  • <excalidraw_not_loaded>

Logic (Logic Gates)

Semi-conductors

  • Explanations:

  • 'Doping' happens with type 'n-type' or 'p-type', but regardless of doping, the Emitter, Base and Collector are electrically neutral. The only polarization that happens is when a 'p-type' and an 'n-type' approach each other, which creates an "electrical barrier" due to the donation of electrons from the 'n-type' to the 'p-type'; this happens for example in the Base <-> Collector or Base <-> Emitter of Transistors.

Transistors

Current in the Transistor

  • The current I_E (Emitter) depends on I_B (Base) and I_C (Collector), being equal to {I_E = I_B + I_C}; this can be approximated to {I_E = I_C}, considering that I_B is basically insignificant when compared to I_C.

  • The current I_C depends on V_CE (Voltage Drop between Collector and Emitter), where V_CE has its value changed based on I_B, via the Beta factor relationship. When the Base "saturates", we will have that V_CE will reach its minimum value, enabling the highest allowed value of I_C.

  • Extreme cases:

    • If {I_B = 0}, this implies that {I_C = 0} and {V_CE = V_CC}, because the circuit will be open (Cut-off).

    • If {I_B = >>}, this implies that {I_C = >>} and {V_CE = 0}, that is, V_CE will be shorted, leaving I_C at its maximum value. This point is called I_C(sat), known as the Saturation Point.

  • Illustration:

    • <excalidraw_not_loaded>

  • Videos:

    • Explanation of the curves that associate I_B, I_C and V_CE: ElectronXLab video .

      • At 13:19  of the video, an example of determining I_B for the Transistor to saturate is shown. 'DC Load Line' is also briefly explained.

    • Calculation of I_B, I_C and V_CE, in addition to drawing the 'DC Load Line' and the 'Q Point': by ElectronXLab  and by ElectronXLab .

      • The 'Q Point' (Quiescent (quiet) Point), is defined as the point of Current I_C and Voltage V_CE when the circuit has no signal; represented as I_CQ and V_CEQ. It can also be said to be the 'Operating Point'.

Voltage in the Transistor

  • The Voltage between the Emitter and the Base will be given by the manufacturing material:

    • Silicon: 0.7 V.

    • Germanium: 0.3 V.

Beta Factor

  • It is a physical characteristic of the Transistor, not of the circuit. It is defined as {Beta = I_E / I_B}.

Transistor Saturation

  • I_B(sat) (Saturation Current) is defined as {I_B(sat) = Beta * I_C(max)}. Any current I_B > I_B(sat) also puts the Transistor in saturation; the only care that must be taken is not to overload the I_BE current, burning the Transistor.

Darlington Transistors

Voltage in the Transistor

  • The Voltage between the Emitter and the Base will be given by the manufacturing material, always being the sum of the Voltage between the '2 Internal BJT Transistors':

    • Silicon: 0.7 * 2 = 1.4 V.

    • Germanium: 0.3 * 2 = 0.6 V.

Current in the Transistor
Beta Factor

  • Beta_D (Darlington's Beta) will depend on Beta_1 and Beta_2 (Beta of the internal BJTs), so that: {Beta_D = Beta_1 * Beta_2 + Beta_1 + Beta_2}; normally the term {Beta_1 + Beta_2} is disregarded, since the contribution of this term in Beta_D is basically insignificant.

  • Example of application with Beta calculation - GVEnsino .

Circuits with Transistors

'Common Emitter' Amplification [?]
'Class A' type Amplification
'Class B' and 'Class AB' type Amplification

  • [I found it confusing] Demonstration and explanations: video .

'Voltage Divider Bias'
'Buffers and Inverters' with Transistors
'Flip Flops' with Transistors
'Toggle Button' with Transistors

Resistors

Capacitors

  • The Capacitor stores charge in the form of 'Electric Field', while a Battery stores charge in a 'Chemical' way. The way in which energy is stored means that the Capacitor cannot store as much charge as a Battery, but allows the charge to be charged and discharged much faster than in a Battery.

  • Capacitors - EngineeringMindset .

  • Series Association:

    • 1/C_eq = 1/C_1 + 1/C_2 + 1/C_n.

  • Parallel Association:

    • C_eq = C_1 + C_2 + C_n.

Circuits with Capacitors

Voltage Multiplier (Voltage-pump) with Capacitors

Color code

Inductors

Transformers

  • Only works with AC; does not work with DC.

  • Everything is based on energy conservation (Power_1 = Power_2): a Transformer can increase the Voltage, decreasing the Current; or decrease the Voltage, increasing the Current.

  • Transformers - EngineeringMindset .

    • At 4:39  of the video, the difference between 120V and 240V is explained.

  • The formula that associates Voltage and 'Number of Turns' is: V1/V2 = N1/N2.

Diodes

  • "When a Diode is active, there is a voltage drop across its terminals", that is, there is a "Voltage drop"  between the terminals.

Heat dissipation