Quartz filters. Schemes, articles of the Free Technical Library

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Quartz filters. Schemes, articles, descriptions

Free library / Schemes of radio-electronic and electrical devices

Quartz filters

We recommend reading in our Free Technical Library:

Non-contact loudspeaker protection

Section Acoustic systems. Most modern audio frequency power amplifiers (UMZCH) are built without coupling capacitors at the output. If the amplifier malfunctions, the appearance of a constant voltage at the output of the UMZCH can damage the expensive speakers of the speaker system. To protect them from direct voltage of any polarity, I propose a simple device (Fig. 1) ... >>

Security device with telephone line alarm

Section Security devices and signaling of objects. It is known that not all citizens who decide to install an alarm in their apartment can afford to use the help of specialized security companies. The author of the proposed article has developed a device that allows you to acquire a periphery system without resorting to their services. The described security device uses a chain of normally closed sensors connected in series. When any of them is opened, it automatically dials a predetermined telephone number an infinite number of times and gives specific sound signals. The subscriber at the other end of the wire, having understood the meaning of these signals, can return the device to standby mode by issuing a command with a DTMF signal, and take care of eliminating the threat to the protected object. A significant drawback of such a device is the need to take special measures to protect the telephone line, since if an intruder cuts the line, it will be neutralized. But more on that at the end of the article. ... >>

Telephone informant

Section Telephony. The proposed scheme (Fig. 1) is a simplified equivalent of autoresponders and informants. When you call, the pulse signal passes through the capacitance C 1 and the diode bridge VD3 on the relay K1. The relay is activated. Through contact K1.2, the power circuit of the tape recorder is closed. Contact K1.1 closes capacitance C1, and a constant voltage of 12 ... 14 V is applied to the relay and the circuit. The relay is self-locking. The intermittent signal generator on the DD1 chip and the threshold device on the DD2 chip are started. The signal from the generator is fed to the VT2 base, the load of which is the internal resistance of the telephone line. The operating time of the generator depends on the charge time of C7 through R7. The threshold device provides the desired operating time of the tape recorder, which depends on the charge time of C8 through R8 and R9. When the device is triggered, transistor VT1 opens and energizes the relay ... >>

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Articles on quartz filters

Articles on quartz filters; circuits of quartz filters; descriptions of quartz filters: 12 articles

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Artificial leather for touch emulation 15.04.2024

In a modern technology world where distance is becoming increasingly commonplace, maintaining connection and a sense of closeness is important. Recent developments in artificial skin by German scientists from Saarland University represent a new era in virtual interactions. German researchers from Saarland University have developed ultra-thin films that can transmit the sensation of touch over a distance. This cutting-edge technology provides new opportunities for virtual communication, especially for those who find themselves far from their loved ones. The ultra-thin films developed by the researchers, just 50 micrometers thick, can be integrated into textiles and worn like a second skin. These films act as sensors that recognize tactile signals from mom or dad, and as actuators that transmit these movements to the baby. Parents' touch to the fabric activates sensors that react to pressure and deform the ultra-thin film. This ... >>

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Random news from the Archive

Pregnancy changes the mother's bones 10.11.2022

Scientists at New York University found that pregnancy can change the mother's skeleton.

A new study shows that even before fertility stops, the skeleton responds dynamically to changes in reproductive status. In addition, these results confirm the significant impact of pregnancy on the woman's body.

During pregnancy, the mother's body can extract calcium from the bones, which reduces the mass, structure and density of the woman's skeleton.

During the study, scientists studied the skeleton of seven macaques, four of which were females. As it turned out, the femurs of females are different from the femurs of males, and this can be explained by lactation and pregnancy.

The bone composition of macaques that have been pregnant is affected by bone resorption during reproduction, but more research is needed to confirm this.

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