Basics:An operational amplifier is a DC-coupled high-gain electronic voltage amplifier with a differential input and usually a single-ended output. High performance op amp integrated circuits still offer excellent value for money, but obviously cost a little more
symbol
Operational amplifier / op-amp circuit symbol
Basic inverting circuit
Basic inverting operational amplifier circuit
formula: Vout=(R2/R1)*-Vin
Basic non-inverting op-amp circuit
Basic non-inverting operational amplifier circuit
formula: Vout=((R2/R1)+1)*Vin
*Before we use the operational amplifier we have to calculate the circuit and find the datasheet of the op amp.
3 & 4 from ECU is 5V it can control LED frequency and bright.
2 is ground.
- Transistors: I choose two of BC547 NPN: Vbco = 50V; Vces(Vbe=0) = 50V; Vceo(Ib=0) = 45V; Vbeo = 6V; Ic = 100mA; Icm = 200mA Ptot(TA<25°C) = 500mW(derate 4mW/°C above 25°C); Tstg = -55 to 150°C. Emitter-Base breakdown Voltage = 6V; Icbo= 15nA; Vce(sat)=0.25V(Ic=10mA,Ib=0.5mA);Vbe(sat)=0.7V(Ic=10mA, Ib=0.5mA); fT= 250MHz
- LED: I choose two LEDs one is red another is yellow, from LED datasheet I know LED voltage is 1.8V and amperage is 20mA. But I searched web the yellow LED has a different of the voltage drop is around 5V.
- Resistors: I used four resistors in this circuit two before the LED positive I called R14 & R15 and the other two before base of the transistors I called R13 & R16. From calculations I know:R14 & R15 = V(12V)-V(LED 1.8V)/A(LED data sheet 20mA) because these are parallel circuit so the voltage same, and from the LED data sheet told us 20mA should flow throw it. So I can calculate how big resistors should in this circuit. R14 & R15 = 510ohms, so I can take below 510ohms of resistor in this circuit. I choose two 470ohms resistors for each LED.
R13 & R16= Vs(5V)-Vbe(0.6V)/Ib(20mA), so R13 & R16 I choose 2200ohms resistor.
When I build this circuit I got a problem from LED, because I choose a LED doesn't work before I use. So when I build it and check the circuit connection all good, than I connect the power supply. But only one LED can bright, than I use multimeter to check available voltage and voltage drop from each component, I found the disconnection LED, so changed it. Than the circuit work well. After I checked available voltage and voltage drop again, when I read from multimeter I find the different colour LED has different voltage drop and available voltage, than I asked tutor also searched from Google, I got the reading is: Green & Red LED about 2.2V; White LED about 3.5V; Yellow LED about 5.5V.
The fuel injector circuit when the engine start injector push throw the fuel into intake valve to the cylinder, when goes to high speed the fly wheel turn crankshaft fast and the piston move up and down fast also engine need more fuel and air. So it made injector open more frequency than idle speed. In this circuit I know if I use high resistance of R14 & R15, the LED will be less bright. It is mean high resistance block lots of current so LED couldn't get enough current throw, also mean injector cannot open very well. If use this experience to the real car problem I would know if I step on fuel pedal but the car couldn't got high speed, and the problem may be from injector leaking. So we can check the voltage drop from each components, if before injector has high voltage drop it will be the high resistance. From other side, the power supply from the ECU to control the frequency of the injectors, when we push down the fuel pedal it will told ECU the car will go fast and ECU will change the frequency for injector.
What is the resistor? A linear resistor is a two terminal, linear,passive electronic component that implements electrical resistance as a circuit element. The current flowing through a resistor is in a direct proportion to the voltage across the resistor's terminals. The ratio of the voltage applied across resistor's terminals to the intensity of current flowing through the resistor is called resistance.
How does it work? A resistor in the circuit we have to read the specification before and choose the right resistor use to the circuit, because if use small one to the high power circuit it will be over heat and fusing so it wouldn't be protect the circuit. But if use large resistance to the low power circuit it will be protect too much electricity throw the circuit so the electrical equipment wouldn't work very well.
How to read the resistor?(Resistor color code)
Calculate Series circuit: Rt= R1+R2+R3+.. Parallel circuit: Rt=R1*R2/R1+R2
Reflection Resistor can block the current flow throw the circuit. In series circuit Rt always large than each resistor. In parallel circuit Rt always smaller than the small resistor.
Diodes
What is the diode?
In electronics a diode is a two terminal electronic component.
How does it work?
The most common function of a diode is to allow an electric current to pass in one direction (called the diode's forward direction), while blocking current in the opposite direction (the reverse direction).
We use three types diodes for this experiment: Diode\ Zener Diode\ LED.
1 Diodes & LED: We use the multimeter,identify the anode and cathode of the diode and the LED. We found when we test voltage drop in forward biased direction we could read the voltage drop of the LED is above 1.80V and the diode is above 0.6V, but when we test voltage drop in reverse biased direction we read the voltage drop of the LED and diode same as infinity. It's mean the current only flow one direction in the diodes, and different diode has different limited voltage drop.
2 Zener diode: from experiment we found the zener diode only can flow through the voltage drop in reverse and constant.
3 Experiment reflection: we use 10V and 15V battery supply, a resistor, a diode and a zener diode. In this experiment we checked the voltage drop of each components and we found the voltage drop on the diode and the zener diode always same as the individual test so is mean on the circuit the diodes can block the current flow throw. The Vs only change the resistor's voltage drop.
Transistor
What is transistor?
A transistor is a semiconductor device used to amplify and switch electronic signals. It is composed of a semiconductor material with at least three terminals for connection to an external circuit.
How to check identify of the transistor?
We use a multimeter turn it to test diode, than use positive leg and negative leg to find which leg is base of the transistor. Because the collector disconnect the emitter but them both connect the base, also we can find the type of transistor PNP or NPN.
How to check the collect and the emitter?
We use a multimeter and set it to diode test, we test base leg with the other two legs and the higher reading is the emitter but the other leg is the collector.
Experiment
From this experiment I checked the voltage between the base and emitter, and between the collector and emitter. I know the 10KΩ can block almost voltage drop but the less voltage drop can flow through between the base and emitter, and it can open the gate, than the collector would connect the emitter so the voltage drop can flow through between collector and emitter.
From this experiment we used a low ohms resistor for Rc and we changed high ohms resistors for Rb between 2K2Ω to 1MΩ, and we checked the voltage drop of the Vbe and the Vce, also we checked the amperage of the base and the collector. We found the Vbe and Ib doesn't change too much when we change the Rb, but the Vce has changed also the current changed of the base and collector. When the Rb is lower the Vce is lower but the Ic is higher, and when the Rb is higher the Vce goes higher but the Ic is lower.
It's told us when the Rb get high resistance the base couldn't get enough current flow through because the high resistance block almost current, so the collector couldn't flow through the current to the emitter but the Vce has high voltage drop. And if the Rb get less resistance so the circuit can flow through more current to the Ib and when the Ib get enough current throw it will be open the gate and collector could connect emitter throw more current.
Capacitor
The capacitor stores electric charge. A capacitor consists of two metal plates very close together, separated by an insulator. When commected to a battery or power source electrons flow into the negative plates and charge up the capacitor.The charge remains there when the battery is removed. The charge stored depends on the "size" or the capacitor, which is measured on Farads
Types of capacitor:
- Non-electrolytic capacitor: Fairly small capacitance-normally about 10pF to 1mF
No polarity requirements-they can be inserted
either way into a circuit
Can take a fairly high voltage.
- Variable capacitor: Adjustable capacitor by turning a knob-similar to variable
resistors.
The maximum capacitance available is about 200pF.
Used in radios.
- Electrolytic capacitor: Large capacitances - 1mF to 50,000mF
Warning: These must be corrected the right way round(polarity)
or They can explode- the white terminal on the diagram above
signifies positive.
Black stripe with "-" shows which terminal is the negative
(Usually the short one)
Low voltage rating-from 25 - 100V DC
They have a significant leakage current - this means that they
will lose the charge stored over time.
- Tantalum capacitor:These have the same properties as the Electrolytic capacitor
but they are physically smaller & have lower leakage. As a
What is the resistor?
A resistor in the circuit we have to read the specification before and choose the right resistor use to the circuit, because if use small one to the high power circuit it will be over heat and fusing so it wouldn't be protect the circuit. But if use large resistance to the low power circuit it will be protect too much electricity throw the circuit so the electrical equipment wouldn't work very well.
1 Diodes & LED: We use the multimeter,identify the anode and cathode of the diode and the LED. We found when we test voltage drop in forward biased direction we could read the voltage drop of the LED is above 1.80V and the diode is above 0.6V, but when we test voltage drop in reverse biased direction we read the voltage drop of the LED and diode same as infinity. It's mean the current only flow one direction in the diodes, and different diode has different limited voltage drop.
2 Zener diode: from experiment we found the zener diode only can flow through the voltage drop in reverse and constant.
A transistor is a semiconductor device used to amplify and switch electronic signals. It is composed of a semiconductor material with at least three terminals for connection to an external circuit.
