barcode in vb.net 2005 An Armstrong oscillator. in Software

Painting QR Code ISO/IEC18004 in Software An Armstrong oscillator.

25-2 An Armstrong oscillator.
QR-Code Reader In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
QR Code Drawer In None
Using Barcode generator for Software Control to generate, create QR Code ISO/IEC18004 image in Software applications.
The frequency of this oscillator is controlled by means of a capacitor across either the primary or the secondary winding of the transformer. The inductance of the winding, along with the capacitance, forms a resonant circuit. The formula for determining the LC resonant frequency is in chapter 17. If you ve forgotten it, now is a good time to review it. The oscillator of Fig. 25-2 is known as an Armstrong oscillator. A bipolar transistor can be used in place of the JFET. It would need to be biased, using a resistive voltage-divider network, like a class-A amplifier.
QR Code Recognizer In None
Using Barcode scanner for Software Control to read, scan read, scan image in Software applications.
QR Code Generation In C#.NET
Using Barcode maker for .NET framework Control to generate, create QR Code image in Visual Studio .NET applications.
The Hartley circuit
Create QR Code ISO/IEC18004 In VS .NET
Using Barcode creator for ASP.NET Control to generate, create QR Code ISO/IEC18004 image in ASP.NET applications.
Painting QR Code ISO/IEC18004 In .NET Framework
Using Barcode maker for VS .NET Control to generate, create QR Code JIS X 0510 image in .NET applications.
A method of obtaining controlled feedback at RF is shown in Fig. 25-3. At A, an NPN bipolar transistor is used; at B, an N-channel JFET is employed. The PNP and P-channel circuits are identical, but the power supply is negative instead of positive.
Printing Quick Response Code In VB.NET
Using Barcode generator for .NET framework Control to generate, create QR Code JIS X 0510 image in .NET applications.
EAN 128 Creator In None
Using Barcode printer for Software Control to generate, create UCC - 12 image in Software applications.
460 Oscillators
Creating USS Code 39 In None
Using Barcode encoder for Software Control to generate, create Code 39 Full ASCII image in Software applications.
Bar Code Creation In None
Using Barcode drawer for Software Control to generate, create barcode image in Software applications.
25.3 Hartley oscillators. At A, NPN bipolar transistor; at B, N-channel JFET.
Drawing European Article Number 13 In None
Using Barcode generation for Software Control to generate, create EAN 13 image in Software applications.
Code128 Encoder In None
Using Barcode generator for Software Control to generate, create Code-128 image in Software applications.
The circuit uses a single coil with a tap on the windings to provide the feedback. A variable capacitor in parallel with the coil determines the oscillating frequency, and allows for frequency adjustment. This circuit is called a Hartley oscillator. The Hartley oscillator uses about one-quarter of its amplifier power to produce feedback. (Remember, all oscillators are really specialized amplifiers.) The other three-quarters of the power can be used as output. Oscillators do not, in general, produce
ISBN - 13 Maker In None
Using Barcode creator for Software Control to generate, create ISBN image in Software applications.
Code 128 Generator In Java
Using Barcode printer for Android Control to generate, create Code 128C image in Android applications.
Team-Fly
Draw EAN 13 In Java
Using Barcode drawer for Java Control to generate, create GS1 - 13 image in Java applications.
Painting GS1 DataBar Expanded In Java
Using Barcode creation for Java Control to generate, create GS1 DataBar Expanded image in Java applications.
AM FL Y
Create Data Matrix In Objective-C
Using Barcode creator for iPhone Control to generate, create Data Matrix 2d barcode image in iPhone applications.
UCC - 12 Generator In .NET
Using Barcode creation for ASP.NET Control to generate, create UPC Symbol image in ASP.NET applications.
The Clapp circuit 461 more than a fraction of a watt of power. If more power is needed, the signal can be boosted by one or more stages of amplification. It s important to use only the minimum amount of feedback necessary to get oscillation. The amount of feedback is controlled by the position of the coil tap.
USS-128 Decoder In C#
Using Barcode recognizer for Visual Studio .NET Control to read, scan read, scan image in .NET framework applications.
Universal Product Code Version A Decoder In Java
Using Barcode reader for Java Control to read, scan read, scan image in Java applications.
The Colpitts circuit
Another way to provide RIF feedback is to tap the capacitance instead of the inductance in the tuned circuit. In Fig. 25-4, NPN bipolar (at A) and N-channel JFET (at B) Colpitts oscillator circuits are diagrammed. The amount of feedback is controlled by the ratio of capacitances. The coil, rather than the capacitors, is variable in this circuit. This is a matter of convenience. It s almost impossible to find a dual variable capacitor with the right capacitance ratio between sections. Even if you find one, you cannot change the ratio of capacitances. It s easy to adjust the capacitance ratio using a pair of fixed capacitors. Unfortunately, finding a good variable inductor might not be much easier than getting hold of a suitable dual-gang variable capacitor. A permeability-tuned coil can be used, but ferromagnetic cores impair the frequency stability of an RF oscillator. A roller inductor might be employed, but these are bulky and expensive. An inductor with several switch-selectable taps can be used, but this wouldn t allow for continuous frequency adjustment. The tradeoff is that the Colpitts circuit offers exceptional stability and reliability when properly designed. As with the Hartley circuit, the feedback should be kept to the minimum necessary to sustain oscillation. In these circuits, the outputs are taken from the emitter or source. Why Shouldn t the output be taken from the collector or drain The answer is that the output can be taken from the collector or drain circuit, and an oscillator will usually work just fine. But gain is not important in an oscillator; what matters is stability under varying load conditions. Stability is enhanced when the output of an oscillator is taken from the emitter or source portion of the circuit. To prevent the output signal from being short-circuited to ground, an RF choke (RFC) is connected in series with the emitter or source lead in the Colpitts circuit. The choke lets dc pass while blocking ac (just the opposite of a blocking capacitor). Typical values for RF chokes range from about 100 H at high frequencies, like 15 MHz, to 10 mH at low frequencies, such as 150 kHz.
Copyright © OnBarcode.com . All rights reserved.