Crystal-Oscillator Circuits

Posted on Feb 7, 2014

The frequency of a crystal-controlled oscillator is held constant to a high degree of accuracy by the use of a quartz crystal. The frequency depends almost entirely on the dimensions of the crystal (essentially its thickness); other circuit values have comparatively negligible effect. However, the power obtainable is limited by the heat the crysta

Click here to download the full size of the above Circuit.

l will stand without fracturing. The amount of heating is dependent upon the r. f. crystal current which, in turn, is a function of the amount of feedback required to provide proper excitation. Crystal heating short of the danger point results in frequency drift to an extent depending upon the way the crystal is cut. Excitation should always be adjusted to the minimum necessary for proper operation. The simplest crystal-oscillator circuit is shown in Fig. 6-2A. An equivalent circuit is shown in Fig. 6-2B. , where C4 represents the grid -cathode capacitance and C5 indicates the plate-cathode, or output capacitance. The ratio of these capacitors controls the excitation for the oscillator, and good practice generally requires that both of these capacitances be augmented by external capacitors, to provide better control of the excitation. The circuit shown in Fig. 6-2C is the equivalent of the tuned-grid tuned-plate circuit discussed in the chapter on vacuum-tube principles, the crystal replacing the tuned grid circuit. The most commonly used crystal-oscillator circuits are based on one or the other of these two simple types, and are shown in Fig. 6-3. Although these circuits are somewhat more complicated, they combine the functions of oscillator and amplifier or frequency multiplier in a single tube. In all of these circuits, the screen of the tetrode or pentode is used as the plate in a triode oscillator. Power output is...

Visit page

Leave Comment

characters left:

Related Circuits

Silent Radio LED sign to Arduino

Working on the brightness problem, I know that the 4017 design did not work well because there was no way to turn off the sign while updating the shift registers. As a result I went back to having...

Laser Microphone

This was a final project for an optics class EE 134 at Stanford. It was an open-ended project to make a fully functioning laser microphone the class was geared to demonstrate optics and photonics...

relay circuits

Remove the 6 mm screw holding on the lower rear fairing cover. This is the black plastic piece the spark plug protectors are attached to. Do not remove the lower rear fairing covers, only the...

Single Capacitor Powers Audio Mixer

Micropower and low-voltage op amps allow you to build high-performance analog-signal processors that require no batteries or wall transformers. Instead, you can use a capacitor as a power source....

Berkeley Bolometer Group - Research

Bolometer systems would be simplified considerably if all components could be made photolithographically on a single substrate. We are developing a design for a single-substrate array with several...

Design of VLSI Systems

Clock signals are the heartbeats of digital systems. Hence, the stability of clock signals is highly important. Ideally, clock signals should have minimum rise and fall times, specified duty...

ARCHITECTURES FOR VIDEO PROCESSING

The first question we would like to answer is: what do we mean nowadays for video processing In the past, more or less till the end of the 80`s there where two distinct worlds: an analog TV world...

DC Lessons In Electric Circuits

A meter is any device built to accurately detect and display an electrical quantity in a form readable by a human being. Usually this "readable form" is visual: motion of a pointer on a scale, a...

New Circuits

Zero consumption Anti-theft High power Code Switch for E-Bike Batteries

This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
Ultrasonic distance finder circuit

The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Simple Metal detector circuit with CD4030

Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Fully automatic watering circuit for flower pots

Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
Simple deep searching metal detector circuit

The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
Sub-Harmonic Bass Converter for Electric Guitars

The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
Echo Depth Sounding Sonar for Boats

In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
100W HiFi Audio Amplifier Circuit

This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
Plant-Pot Water Level Indicator Circuit

A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....

Create NOW your QR MENU for your Restaurant / Hotel / Bar / Caffe,

Comprehensive ordering/paying features. fully personalized to suit your Business.

Update Anytime! Easy and Simple!

Popular Circuits

FM Wireless Mic

FM Wireless Mike can transmit voice signals to any FM Radio receiver 100 meters away. The circuit...

5V regulated power supply

his circuit is just an implementation of the 7805 integrated voltage regulator. What this little...

Circuits

In order to avoid any soldering mistakes, I asked students to place all there resistors in the...

Converter for producing a fixed AC from variable AC

For household or industrial application purpose, we are bound to use fixed ac voltage input. If...

wideband output amplifier circuit

This is a simple design for wideband output amplifier. The wideband amplifier is suitable for use...

Serial To Parallel Converter

This converter may help if just the serial port on a personal computer is free, whereas the...

bcd counter 7 segment display

I`m doing this lab BCD COUNTER and 7 SEGMENT DISPLAY and im using CD4510BMS presettable BCD...

THE ZX97LITE SCHEMATIC

I designed the ZX97 as a discrete copy of the ZX81, which was the first PC for millions of...

AC contactor silent operation of the circuit

AC contactor has a silent operation of the circuit due to energy-saving effect is remarkable, no...

Schematic circuit diagram of low voltage and low voltage automatic conversion

Below is automatically converted to low-voltage circuit. 220V electricity through step-down...

Cordless telephone voice processing circuit diagram

CX9800 models of mobile phones and desktop PC have chosen excellent performance voice processing...

DC supply voltage circuit indicates one of the more limited

DC power supply under-voltage, over-voltage indicator circuit shown in Figure 13-93, use it to...