Wiring Schematic diagram: crystal

Friday, November 7, 2014

Police Lights associate crystal rectifier Project

This circuit uses a 555 timer that is setup to each runn in associate Astable operative mode. This generates a nonstop output via Pin three within the type of a sq. wave. once the timers output changes to a high state this triggers the a cycle the 4017 4017 decade counter telling it to output consecutive sequent output high. The outputs of the 4017 ar connected to the LEDs turning them on and off. Schematic
Parts List

1x - NE555 Bipolar Timer
1x - 4017 Decoded Decade
6x - 1N4148 Diode
1x - 1K Resistor (1/4W)
1x - 22K Resistor (1/4W)
2x - 4.7K Resistor (1/4W)
6x - 470 Resistor (1/4W)
1x - 2.2µF Electrolytic Capacitor (16V)
2x - BC547 NPN Transistor
2x - LED (Blue)
2x - LED (Red)
1x - 9V Voltage Battery

crystal radio parts

crystal radio parts
The Basic Crystal Radio is just this much:

A coil, Variable capacitor to tune frequency, a crystal Diode and a High Impedance headphone, makes a crystal radio. You require a very good antenna and good ground. The .001 capacitor is to remove radio frequency from signal & get audio only for phones.

In this project, I am using above circuit already, for those interested only up to this level. So that a crystal Radio remains a crystal radio in its original form. You have an option to use High Impedance earphone and listen this radio without power.
However, in addition to basic circuit, I decided to add some amplification for the very basic reasons that, it was hard to find a High Impedance earphones and second, it was more pleasant to listen to a radio thru a speaker. Crystal Radio Document download

Comparator Based Crystal Oscillator Wiring diagram Schematic

Although a simple crystal oscillator may be built from one comparator of an LT1720/LT1721, this will suffer from a number of inherent shortcomings and design problems. Although the LT1720/LT1721 will give the correct logic output when one input is outside the common mode range, additional delays may occur when it is so operated, opening the possibility of spurious operating modes. Therefore, the DC bias voltages at the inputs have to be set near the center of the LT1720/LT1721’s common mode range and a resistor is required to attenuate the feedback to the non-inverting input. Unfortunately, although the output duty cycle for this schema is roughly 50%, it is affected by resistor tolerances and, to a lesser extent, by comparator offsets and timings.

Comparator Based Crystal Oscillator Circuit Diagram

If a 50% duty cycle is required, the schema shown here creates a pair of complementary outputs with a forced 50% duty cycle. Crystals are narrow-band elements, so the feedback to the non-inverting input is a ﬁltered analogue version of the square-wave output. The crystal’s path provides resonant positive feedback and stable oscillation occurs. Changing the non-inverting reference level can vary the duty cycle. The 2k-680Ω resistor pair sets a bias point at the comparator + (Comparator IC1a) and – (Comparator IC1b) input. At the complementary input of each comparator, the 2k-1.8k-0.1µF path sets up an appropriate DC average level based on the output.

IC1b creates a complementary output to IC1a by comparing the same two nodes with the opposite input. IC2 compares band-limited versions of the outputs and biases IC1a’s negative input. IC1a’s only degree of freedom to respond is variation of pulse width; hence the outputs are forced to 50% duty cycle. The schema operates from 2.7V to 6V. When ‘scoping the oscillator output signal, a slight dependence on comparator loading, will be noted, so equal and resistive loading should be used in critical applications. The schema works well because of the two matched delays and rail-to-rail outputs of the LT1720.

Source by : Streampowers

Wiring Schematic diagram

Friday, November 7, 2014

Police Lights associate crystal rectifier Project

Thursday, November 6, 2014

crystal radio parts

Friday, September 12, 2014

Comparator Based Crystal Oscillator Wiring diagram Schematic

Comparator Based Crystal Oscillator Circuit Diagram