How do you calculate the resistance of a collector?
We calculate a value for RC and choose a close standard value. An emitter resistor which is 10-50% of the collector load resistor usually works well….Example Calculations:
| Bias circuit | IC β=100 | IC β=300 |
|---|---|---|
| collector feedback bias | 0.989mA | 1.48mA |
| emitter-bias, VBB=10V | 1.01mA | 2.76mA |
| emitter-bias, VBB=2V, RB=470 | 1.01mA | 1.75mA |
What does a collector resistor do?
The purpose of the collector resistor Rc is to set the collector current Ic as well as the emitter- collector voltage Vce. In other words, Rc helps to set the transistor at the “operating point” of the ampli- fier.
What is output resistance of CC amplifier?
A common-collector (CC) amplifier typically has a high input impedance (typically in the hundred kΩ range) and a very low output impedance (on the order of 1Ω or 10Ω). This makes the common- collector amplifier excellent for “driving” small loads.
What is the output resistance of CC transistor?
What is the output resistance of CC transistor? Explanation: The CC transistor has a very low value of output resistance of 25 Ω. The voltage gain is always less one. It is used for driving a low impedance load from a high impedance source.
Do I need a resistor on the collector of transistor?
The resistors are used as a means of generating voltage drops and thereby pulling the transistor into the desired operating region. because you need to limit the current to semiconductor terminals. otherwise, the transistors will be damaged.
How is collector current calculated?
Collector Current:
- IC = βFIB + ICEO ≈ βFI. B
- IC = α I. E
- IC = IE – I. B
Why is a pull-up resistor needed for an open collector gate?
A pull-up resistor is a resistor used to keep a given point in a circuit HIGH when in the active state. Why is a pull-up resistor needed when connecting TTL logic to CMOS logic? An open collector output can current, but it cannot . A universal logic gate is one, which can be used to generate any logic function.
What is the input resistance of an op amp?
The input resistance of the ideal op-amp is infinite. However, the input resistance to a circuit composed of an ideal op-amp connected to external components is not infinite.
What is the input resistance of a CC configuration?
In CC configuration, the input resistance is high and the output resistance is low. The voltage gain provided by this circuit is less than 1. The sum of collector current and base current equals emitter current. The input and output signals are in phase.
How do you select a resistor for a transistor?
Choosing a transistor and base resistor for a digital IC output
- Choose the right type of transistor, NPN or PNP.
- Find out the supply voltage(s) and load properties.
- Work out the transistor properties required.
- Work out a value for the base resistor R.
- Check if you need a protection diode.
Why is a resistor connected to the collector of a transistor?
How does collector current increase?
Collector Current It increases for larger emitter currents because the larger number of electrons injected into the base exceeds the available holes for recombination so the fraction which recombine to produce base current delines even further.
What is a weak pull-up resistor?
a “weak internal pull-up” is a pullup resistor that is weak, i.e. a fairly high value, so only a small current. “A single control bit can turn on all the pull-ups” means all the weak pullups can be turned on (or off) by controlling a single bit, which is named “RBPU.
How is collector voltage measured?
This can be done using the formula: Vcc = Vrc + Vrb + Vbe + (Ic + Ib)Rc + IbRb + Vbe, where “Vrc” is the voltage across the collector resistor; “Vrb” is the voltage across the base resistor (connected across the base) and the junction between the collector resistor and the transistor collector; and “Vbe” is the voltage …
What is the output resistance of op amp?
As can be seen from the diagram, the op amp output resistance is the DC resistance that appears in series with the output from an ideal amplifier located within the chip. In other words the output resistance can be measured by looking at the voltage drop caused when a defined load is added to the output.
What is input and output resistance?
The output impedance refers to the impedance, or opposition to current flow, of the component that often bears an electrical source to “drive” a load component. Meanwhile, the input impedance refers to the load component’s opposition to current flowing in from the electrical source.
How do you calculate DCDC resistance?
DC Resistance – calculation For solid conductors the resistance (theoretically) can also be calculated using the standard formula: If the length (l) is in metres, cross sectional area, a in m 2 (mm 2 x10 -6) and resistivity ρ in Ω-m, then the Resistance will be in ohms.
What is the international standard for DC resistance?
To get started, this post will look at the simpler case of dc resistance and how it can be calculated. The international standard for conductors is IEC 60287. The standard classifies conductors according to four classes:
What is the voltage gain and capacitance of the collector?
The voltage gain is about and the collector capacitance is 11 (3 pF) = 33 pF. Because RF is so small, τ T / RE is significant. The series collector resistance <20Ω.
What is the transistor emitter/collector resistance at saturation?
In saturation, the transistor emitter/collector resistance Rec = Ron where Ron is a small but nonzero resistance. The collector current Ip that flows under saturation conditions can be shown to satisfy the following differential equation: where Vb is the vehicle power bus voltage and Lp is the primary coil inductance.