Function zener

Of the myriad components available to electronic designers, zener diodes are among the handiest and strangest. Similar to normal semiconductor diodes in most respects, they also regulate voltage and are designed to work backwards. Their reliability, low cost and small size make them a good choice when a circuit needs constant voltage. Function zener A zener is a kind of semiconductor diode. As with other diodes, it prefers to conduct current in one direction. Normal diodes have a reverse breakdown voltage; no current will flow opposite to the preferred direction, but if the voltage is more than the breakdown value, current will flow and damage the part. A zener, on the other hand, won't be damaged as long as the current is under the device's limit. Used this way, the voltage across the zener will be a constant value determined by the diode itself. They are commonly available in the range of 1.8 to 200 volts. Identification Being a diode, a zener is a small part with two leads and usually a band on the body indicating polarity. The body may be glass, plastic, or metal. It's hard to tell zeners apart from other diodes, however. The best way of telling is by having the schematic handy, or looking up the part number. Considerations Zeners, like other diodes, can conduct only a limited amount of current. Too much current will cause the diode to short out, which could immediately destroy it. This means they're used in low-current parts of a circuit, such as a voltage reference that controls higher-current-carrying transistors. Expert Insight Being semiconductor diodes, zeners are temperature-sensitive. If it's an issue, good circuit design can compensate for this. Because of competing internal effects that cancel each other out, a 5.6V zener is much less sensitive to temperature than ones with lower or higher voltage ratings. Benefits Some devices, like flashlights, portable radios and toy cars, work fine for a range of voltages. Many electronic circuits, however, need a constant voltage somewhere in the design. Zeners are an easy-to-use, low-cost way of achieving good voltage regulation.

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Half-wave rectifier

As the rectifier voltage, the diode is used to convert alternating voltage (AC) into DC voltage (DC). Rectifier voltage have 2 kinds, namely: 1. Half-wave rectifier (half-wave rectifier) 2. Full wave rectifier (full-wave rectifier) 1. Half-wave rectifier (half-wave rectifier) When used as a half-wave rectifier, diode voltage direction AC

Rectifiers are often called into action to measure signal strength. Rectify an AC signal, pass it through a low-pass filter and the resulting DC level represents some measure of the signal's magnitude. Although the series diode is the classic rectifier, it can't rectify signals smaller that it own forward voltage! But what if your expected amplitude can be as low as 100 mV? Op amps to the rescue! The advantage of op amp circuits lies in their ability to compensate for non-linear devices in the feedback loop. Combining the rectifying action of a diode with the accuracy of an op amp, this circuit creates a precision rectifier.

Half-wave rectifier (half-wave rectifier)
When used as a half-wave rectifier, diode menyearahkan shaped AC voltage into DC voltage sine wave only during the positive cycle of AC voltage only. Meanwhile, during the negative cycle, the diode having panjaran back (reverse bias) so that the load voltage (output) to zero.

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microhenry

Electrical inductance sensors are non-contact devices that measure the inductance of an electrical component or system. They consist of a wire loop or coils and are relatively inexpensive. Inductance, the property of a circuit or circuit element to oppose a change in current flow, refers to the capacity of a conductor to produce a magnetic field. The standard unit of inductance is the Henry (H). Because the Henry is a large unit, electrical inductance sensors often measure inductance in microhenry (µH) or millihenry (mH) levels.

Electrical inductance sensors contain a nickel-iron core shaft that rotates within the coil around the material. The inductance measured by an electrical inductance sensor depends on the number of turns in the coil, the type of material around which the coil rotates, and the radius of the coil. With the rotation of the shaft, displacement occurs within the coil and generates inductance. This displacement produces signals that can be measured by an inductance meter and recorded. Most inductance meters are digital, hand held devices suitable for measuring inductance of very low value. The results of the inductance calculation can be plotted as a graph for future study.

Selecting electrical inductance sensors requires a careful analysis of product specifications and application requirements. Most electrical inductance sensors have a standard accuracy variance of less than 0.5% when measured on full scale. For best results, an electrical inductance sensor should be able to generate an output signal of at least 4-20 mA. Typically, a sensor’s measurement range is approximately 30% of the coil diameter. For high precision measurements, the thickness of the coil should be at least 0.025 inches (in.).

Electrical inductance sensors are used in many different applications. Some electrical sensors are used in the automotive industry and the power industry. Other electrical sensors are used in constructing planar transformers, generating electrical magnetic fields, and monitoring the inductance of an electrical component. Electrical sensors such as electrical inductance sensors are widely used for detecting the presence of electrical voltage in equipments, and defective gro

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Antenna diplexer

Antenna diplexer
- A brief overview, a tutorial on the basics of antenna or RF diplexer diplexer used for purposes including enabling a single RF antenna for use by several transmitters ..

An antenna or RF diplexer diplexer is a unit in a single application can be used to allow more than one transmitter to operate on a single RF antenna. Sometimes these units can be called antenna duplexers. Typically an antenna diplexer will allow the transmitter to a different frequency operation using the same antenna. In other applications, an antenna diplexer can be used to allow a single antenna to be used for transmission on one frequency band and receiving on other bands.

Antenna diplexers find many uses. In one common example of an antenna or RF diplexer diplexer used in cellular base station to allow it to send and receive simultaneously. The diplexer antenna allows the system to use the same antenna while preventing the transmitted signal from reaching the receiver and the input block. In other applications diplexer may be used by broadcast stations transmitting at different frequencies at the same time using the same antenna. Use of diplexer allows a single antenna to be used, while preventing the output of a transmitter which fed back into the other output.

Diplexers small antennas can be used in a domestic environment to enable multiple signals to run along a single feeder. In one application may allow a single feeder to be used for television and VHF FM radio reception, or to allow television signals from terrestrial and satellite voice box low (LNB) to pass on the same lead. This RF diplexers are usually relatively low cost as not nearly as demanding specifications that are used for professional installation of the RF diplexer.

Basic concept of antenna diplexer

There are a number of ways to implement the RF diplexers. They all involve the use of filters. In this way the path to a different transmitter and receiver can be separated according to the frequency they use. The easiest way to implement the diplexer is to use low pass and high pass filter despite the band-pass filter can be used. In this way diplexer routes all signals at frequencies below the cut-off frequency of low pass filter to one port, and all signals above the cut-off frequency high pass filter to another port. Also here are the street from between two long-distance from the filter. All the signals that can pass through low pass filter in the diplexer will not be able to pass through a high pass filter and vice versa.

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microcontroller chips

microcontroller chips appear on the market, today’s microcontroller programming tools are becoming more and more ‘universal’ to cope with different programming conventions. It is also sadly the case that the more ‘universal’ the programmer, the more you need to pay. In practice, most people will only use a fraction of the capabilities of such a programmer, making it difficult to justify such an expense. The project here describes a minimal solution to the programming problem for one of the most popular types of controller. The PIC16F84 (1k-Flash-memory) and the PIC16C84 (1k-ROM) with 13 I/O-lines.

Using a PC together with this relatively simple interface and some software it is possible to build a low cost programmer The design for the programmer is described on the author’s website. The programmer connects to the serial port of a PC. Pin 3 of the port supplies the power and zener diode D6 along with D5 regulates the supply to the chip at 5 V. C1 and C2 smooth the regulated supply. The unregulated supply is fed to pin MCLR of the PIC to configure it in programming mode. R1 limits current into this pin and an internal regulator ensures the correct programming voltage on chip. A high on this pin switches the PIC into programming mode.

Data exchange between the PC and the PIC occurs over the lines TxD (Pin 3), DTR (Pin 4) and CTS (Pin 8) and can be viewed on the LEDs D2, D3 and D4. A control software package comprising NTPICPROG, PIX and Euro13 for Windows and DOS (altogether 198 kB) can be downloaded free from the ‘Elektro’ page of the authors website at

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KIA555P

The KIA555P monolithic circuit is a highly stable device for producing accurate time delay or timing pulse. Additional terminals are provided for triggering or resetting if desired. In the time delay or monostable mode of operation, the time is precisely controlled by one external resistor and capacitor. In the astable mode of operation, the frequency and duty cycle are accurately and independently controlled with two external resistors and one capacitor. The circuit of the KIA555P may be triggered and reset on falling waveforms, and the output structure and source and sink up to 200mA or drive TTL circuit. Operation is specified for supplies of 5-15V. Features: Timing from Microseconds Through Hours Operates in both astable and monostable modes Output can source or sink 200mA Output TTL compatible Temperature stability of 0.005%/ °C typ Normally On or Normally Off output

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RMS to DC Converter

RMS to DC Converter series. To measure the RMS value of alternating voltage of a converter is needed to produce accurate RMS value of the input alternating pure as DC output. With a simple sinewave input RMS voltage can only be calculated as 0.707 times the peak AC voltage, but with a complex waveform calculation is hardly easy. RMS value is defined as a DC voltage which will give the same heating effect in a resistor as an alternating voltage. LTC 1966 from Linear Technology uses a new form of delta-sigma conversion and is designed for battery operation, only draw 170μA of supply. The new technique is accurate to 0.02% between 50 mV and 350 mV and very linear. It can operate from 50 Hz to 1 kHz (with an error 0.25%) and up to 6 kHz with an error of 1%. Anyway, for more details, please refer to the schematic drawings and learn the RMS to DC Converter circuit below.

The following are important things to note from the RMS to DC Converter series. Input voltage range on the differential inputs IN1 and IN2 to the additional input supply rail, and non-symmetrical circuit shown here at the IN1 voltage can swing between 0 V and the supply voltage. If the signal to be measured is AC only, the other coupling capacitors are required. Input impedance is some megaohm. Output voltage at the OUT pin can be offset by applying a DC voltage to pin OUT RTN. This is especially helpful when using the device with a multimeter as LCD IC 7106. A capacitor is further connected to the output that is charged to the voltage required by the switched-capacitor circuit in the converter. Capacitors required is ten times smaller than that demanded by the previous RMS to DC converter designs. This allows small RMS to DC converter to be built using only four components

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