Conex Club Magazine - no.4 - 2002

Conex Club Magazine - no. 4 - 2002 - Rapid manufacture of printed circuit boards using engraving technologies

Reading time: 4 minute

The main topics presented

1. TPS6021X (Regulated 3.3-V 50-mA Low-Ripple Charge Pump with Ultra Low Operating Current)

The TPS6021X product range forms a family of DC / DC converters which is powered by voltages between 1.6V and 3.6V offers 3.3V output and current between 50mA and 100mA.

Batteries are used as a power source NiCd or LiMO2. These converters are used in portable medical or industrial equipment.

2. AD698 (Universal LVDT Signal Conditioner)

The AD698 circuit is intended for the interface function for the analog signals obtained by linear displacement sensors (magnetostrictive, microwave, laser, LVDT - linear variable differential transformer).

LVDT signals come from the movement of a magnetic core inside a coil thus being able to measure movements, pressures, etc., with great accuracy.

The signal used for measurements comes from an internal oscillator, with the frequency between 20Hz and 20kHz. The circuit works in the temperature range: -40C and + 85C.

3. Rapid manufacture of curcumin printed by engraving technologies

Industrial manufacturing of printed circuit boards involves the use of special technologies, based mainly on extremely complex chemical and electrochemical methods and techniques.

Strict observance of the technological flow within the specialized factories leads to obtaining high quality PCB structures, other advantages being the realization without difficulties of a large number of identical boards, professional metallization of some articles (through holes) or areas (printed connectors, certain contact areas) or the possibility of depositing layers and non-electric protective or inscription masks.]

Disadvantages of industrial manufacturing

There is, however, a small one disadvantage (felt especially by small businesses or amateur electronics) which does not seem to be very easy to overlook: rapid manufacture of unique, prototypes or very small series of printed circuits.

The reason for the problems is that the manufacturing flow is identical, regardless of whether it is a plate or 1000 plates, in both situations requiring complex preparations in various stages, making molds, masks or sieves, using equipment large size and highly qualified staff.

In these conditions, a PCB unique will leave the factory gate after good days from receiving the manufacturing files.

As the companies developing electronic products have increasingly demanded the finding of technological solutions for the rapid manufacture of printed circuits at the level of prototype / very small series, in the last decade. intense efforts have been made to find solutions that combine the need to maintain a high quality with that of drastically reducing working time.

LPKF from Germany

Company LPKF from Germany managed to meet these conflicting requirements by replacing standard technology with one based on methods of mechanical etching of copper foil.

Thus, by means of very small cutters, the isolation of the routes destined to the interconnection of the electronic components takes place or even total removal of conductive areas in the case of applications intended for high frequency work.

The coordinate drilling operation is performed by means of the same equipment and is practically similar to that of the industrial process.

4. Wireless microphone

In the laboratory of Conex Electronic, an a was designed and builtassembly consisting of an electret microphone and a frequency-modulated mini-transmitter operating in the 88-108MHz frequency band.

It is powered by 2 batteries type R6 or R03 and consumes less than 20mA (at 3V supply voltage) and provides a power of the order of a 4mW.

The assembly was made on a plate with printed wiring with dimensions 23 x 58mm.

5. PIC programmer, EEPROM and SIM cards

For electronics that have noticed the advantages of using the microcontroller PIC16F84 </strong> Microcontroller. in schemes with the most diverse applications, it becomes a problem to choose the most suitable programmer and the easiest program necessary to program the device.

The analysis of the proposed schemes demonstrates the imperfection of some or at best the fact that they are unifunctional.

The result of long research and repeated optimizations has materialized in what can be called a "Multiprogrammer".

The proposed installation is the simplest and safest microcontroller programming device in the series PIC16x84, serial EEPROMs with data transmission on one or two wires and SIM cards blank or manufactured with ordinary chips.

6. Complex alarm system

The article presented is based on "joining" assemblies as well as some articles representing in essence an alarm system that through the way of presentation, through the ways in which it can be "articulated" in different configurations can detect the penetration of the supervised space or can represent a source of ideas or achievements for those interested.

7. TV modulator

Motorola produces the specialized integrated circuit MC 1374 P with the help of which a modulator for television, image and sound signals can be built.

The maximum working frequency of this circuit is 105MHz and thus modulators can be made in TV channel limit 1-5 OIRT.

Using this integrated circuit, a TV modulator was created that covers the frequency range in the channel gap 1-3 OIRTS.

The electrical parameters of the MC 1374 integrated circuit were presented in issue 1/2002 (page 30) of the Conex Club magazine

8. Remote control through the electrical network

The wires from the electrical network, mounted inside a building, are used as a support for the transmission of remote control signals during this installation.

The transmitter contains a circuit of the type CD 4011 of which two gates (3 and 4) form an oscillator with a frequency of approximately 1.3kHz which modulates a carrier generator with a frequency of 125kHz.

9. Measurements with the reflectometer

Intended for measuring the mode of transmission of energy on long lines, the reflectometer is an indispensable device for professional and amateur radiocommunication stations.

Thanks to this accessory we can control how much energy from the transmitter is transmitted to the antenna and how much energy is returned.

The construction of the reflectometer is dictated by the range of frequencies where it will be used, by the power of the transmitter, but also by the accuracy of the measurement to be performed.

Specialized companies build the reflectometer, but amateurs also build.

It is important to know how to use a reflectometer, to correctly interpret the measurements performed in order to be able to intervene properly and where it is necessary in the transmission chain so that the radio frequency energy reaches the antenna (and radiated) and not turns into caloric energy.


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