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....

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....

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.....

In this page we will show how you can simply construct such a meter, which is good to have one, to show not only the existence of radioactive materials but also the dangers arising from them. The Geiger–Müller counter can be compared to a photometer. The....

Modems are devices that connect either remote devices to a computer, or two or more computers to each other. Their connection is usually wired. The GSM modem we present is wireless. It can connect two computers, a computer with the internet or even be the....

This circuit is an amplifier for small transmitters operating in the UHF band, specifically in the 450-800MHz range. The amplifier works in class A and we used the well-known Philips BLW33 transistor for its manufacture. The construction, although simple,....

This amplifier is intended for amplifying low signals from oscillators in the FM band. It does not have frequency regulators with variable capacitors and coils, it has a wide range and moderate power capable of driving several linear amplifiers. The whole....

SGS Thomson's integrated TDA7294 is a high-frequency acoustic power amplifier, with true high-precision specifications, suited for all relevant applications. Its main feature is much higher output power than is usual in amplifiers with similar distortion....

This circuit consists of a 2048 radio remote control transmitter and the corresponding wireless receiver with very high reception sensitivity and low consumption. The combination of the two above gives a high-reliability remote control, ideal for security....

At the left side (input AC) goes the secondary of a 220 volt (primary) 18 Volt (secondary) / 3 Ampere mains transformer. The alternating voltage of 18 volts from its secondary transformer is rectified by the diodes D1, D2, D3 and D4, which are connected to a....

It is a simple and reliable system for processing human speech. It has the task of altering the tone of the human voice and making it heard as artificial, such as the voice of a robot that, as it is known, is produced by artificial means. This is an easy but....

The design of the 40W Valve Amplifier is shown in the figure. In valve amplifiers the predominant feature is the strong presence of the second and third harmonics, sometimes in agreement with the fourth and fifth, but always with a much wider width. Higher....

This project is influenced by the effort to achieve a security system that can be used in the business, or even very simply at the door of your home. This security system uses the microcontroller of the Arduino Uno system in combination with RFID (radio....

This pulse generator produces square pulses from 1Hz to 100KHz with adjustable pulse width of nearly 0-100%. The generator is powered with a voltage of 5-15V and is therefore suitable for both TTL and CMOS circuits. If you want to measure the response of an....

This project is an electronic lock with many combinations that you can easily change and opens only with the correct combination of four consecutive numbers. The big advantage of the electronic lock is that the four numbers must be entered in the correct....

This circuit really is the simplest inducer balancing metal detector (IB, Inductlon Balance) that can be built. The LB metal detection method has a satisfactory depth of penetration and good distinction between iron-based and noble metallic objects. Several....

This small device, intended primarily for modellers, allows an instant reading of the time I of a pulse in ms. It can, for example, measure the position of the servomotors, about 1 to about 2 ms, or make repetitive or non-pulsed measurements, such as closing....

The vu-meter is distinguished in two categories, those with the needle instruments and those with the led column. Whether it is a tube amplifier or integrated amplifier, a vu-meter sound level meter is required. Today there are enough chips that do this work....

It is common that sometimes we need to power some devices σuccessively one after the other. This function forces us to handle a large number of switches, which are located where the access is difficult, especially in the case of informational devices and....

The amplifier feeding to the final amplification stage is performed with unstabilized voltage. The output stage, due to push-pull operation, has a large rejection of the supply voltage. The various other steps, however, do not have the same rejection and....

This transmitter works in the short waves from 6MC / S to 22MC / S. Coil L1 is the short wave oscillating coil of the 6SA7 lamp and you will find it ready for trade. Capacitor C1 is variable with a capacity of 0-500pF. The coil L1 consists of 13 coils 3cm in....

These two amplifiers are of very good quality, simple and economical in their manufacture. They have two inputs for a 4mV (500KΩ) sensitivity microphone and an input for any 200mV (1MΩ) sound source, that is, the first input is for speech and the second one....

The simplicity of this transmitter compared to its very high performance makes it very interesting. Its output power is about 30 W and its range under normal conditions, with proper antenna and handling, reaches 30 km. The oscillator is the PL 84 which....

The amplifier of this design is 30 Watt and is suitable for microphone-inducing. It accepts a crystalline microphone and can be used for speeches, lectures, as a transmitter modulator and generally where it can be useful as a common frequency amplifier. The....

In this circuit, the wearer assembly consists of only one lamp, 6V6 or 6L6, which acts as an oscillator and as an output amplifier at the same time. Coil L1 is the medium wave oscillation coil. Of 6SA7. The coil L2 consists of 50 spools wrapped on a cylinder....

It consists essentially of three stages and gives the antenna a power of 300 WATT, provided it is properly tuned. The first tier is an oscillator that has an oscillating coil L1 that will be required by the market as a 6SA7 coil. The coils L2 and L3 consist....

FIG automatically shut down by the circuit is a MOS FET to achieve. When the headset is inserted, the contact off, MOS tube grid connected high, the tube guide pass., feet grou..

Electronic tube amplifier lovers started his art that simple, excellent single-ended Class A circuit should be the first choice. Single-ended Class A tube amp with a mellow, sw..

Figure 4-7 pitch analysis using the relation obtained above design calculation control circuit, where Ai is a buffer to put the big stage, to reduce the burden preamp output. L..

Constituted by a circuit block diagram MAX1463 precision pressure detection system as shown in FIG. Bridge pressure sensor output voltage connected to the MAX1463 IN1 +, IN1- e..

Diagram 2 shake tube n. Capacitance C. Trigger voltage rectifier filter element. H is a trigger voltage transistor amplifier circuit, three pull tube n, U, v. Composition trigg..