The frequency measurement is one of the most important things in radio construction. Without it you will be unable to set desired frequency in your receiver (and in transmitter too!), without it you will be unable to monitor frequency drifts etc. Sometimes, frequency counter can be used to verify, whether the oscillator works and ensure the stabil
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ity of the generation. Measurement of the frequency with ultimate precision, compared to other measurements is incredible simple. You may easily measure 1 MHz frequency with resolution 0. 1 - 1 Hz and precision up to 1-5 Hz. Could you measure 1V with precision 5 microvolts I think, no and never! The idea of frequency measurement is quite simple - you just count the number of impulses during fixed time interval. If the time interval has length 1 second, the result will be directly in hertz. The precision is determined only by precision of time intervals, but the latter are usually formed from high-stable quartz oscillator. Typical counter consists on the following parts: reference oscillator, counter with indication, input trigger and control circuits. Reference oscillator together with control circuits forms fixed time interval as well as reset impulses for counters. The input signal passes through input amplifier and trigger, becoming the levels used by ICs. Then the impulse sequence formed goes to the `gate`, which periodically opens for precise time determined by control circuit. During this time, counters accumulate the result, which is displayed. The structure diagram of my unit is shown below: In my unit to add to all standard parts internal memory triggers are introduced to make measurements more convenient and fast. If output indicators are connected directly (trough corresponding decoders) to the counters, the...
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....
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....
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....
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,....
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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