This circuit can be used from low frequencies to at least 120MHz using series resonant crystals on their fundamental or overtone mode. The output can be taken from the feedback tap as shown, a low impedance winding on L2 or from the drain of the J310 via a low value capacitor. The following stage should be used a a buffer to isolate subsequent sta
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ges from the oscillator. The combined series value of C1 and C2 resonates with inductor L1 at the desired frequency and crystal X1 must have a fundamental or overtone series resonance as appropriate at the same frequency. C2 is about five times the value of C1 Inductor L2 is generally only required at frequencies above about 60MHz and must be chosen to resonate with the total parallel capacitance of X1 at the frequency of oscillation. If the circuit shows signs of free running oscillation controlled by L1 then L2 will be required. The parallel capacitance of X1 will typically be 4 - This circuit is primarily intended for use as an overtone oscillator and will work from 20MHz to 120Mhz depending on the crystal and active device. Operation is extremely stable but the output level is fairly low - pk. L1, C1/C2 and the input capacitance of the transistor act as a quarter wave network, converting the low impedance series resonance of the crystal into a high impedance parallel resonance at the base of the transistor. C1 may not be needed at higher frequencies depending on the internal base/emitter capacitance. This circuit is a Colpitts fundamental mode parallel resonant oscillator for crystals designed for use with a 30pF load capacitance. Values shown are suitable for 8 - 12Mhz and will require changing for significantly different frequencies. Transistors TR1 and TR2 should be characterised for the required frequency range....
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....
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....
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....
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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....
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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....
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....
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.....
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