This RF probe can be used at High Frequency (HF) or Ultra High Frequency (UHF) on both 50 and 75 ohm coaxial cables. In addition the RF voltage can be measured under load or no-load conditions which allows the circuit to double as an RF Watt meter. The RF probe can be used for oscillators and small transistors for powers up to 2 Watts. The circuit
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is a simple half wave rectifier. In this circuit it works at radio frequencies (RF) and converts any RF signal to a DC voltage, in addition S1, allows a resistive load to be switched in or out of circuit. S1 is a single pole, double throw switch with a Centre off position. The centre position is no load, and left and right positions 1 are for 50 and 75 ohm measurements. First, a small section on measuring RF voltage, current and power, then I`ll describe how to use this simple test instrument. Digital and analogue multi meters can already measure AC voltages so why can`t they be used at radio frequencies The reason is that they can only measure with accuracy a limited frequency range. My Maplin meter measures frequencies up to 400Hz with 1% accuracy, and up to 20KHz at 4%. This also requires that the waveform is a sine wave. At frequencies above 20KHz, accuracy is not reliable. To measure radio frequencies (RF) a simple diode detector circuit is all that`s needed. The detector in this probe is an OA91 germanium diode, but any germanium diode will work. Germanium diodes have a low forward voltage drop (about 0. 2V) and are preferred to silicon diodes which have a higher (0. 6 - 0. 7V) voltage drop. The diode rectifies the RF signal and converts it to a DC voltage, which can be read by a multimeter with good accuracy; the 1nF capacitor is there to smooth the rectified DC signal presented to the meter. When measuring any AC...
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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