• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.9
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• pp.484-489
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• 1999

This paper deals with the design and fabrication of a heater-trigger type high-Tc superconducting power supply system, and characteristics have been analyzed through experiments. The high-Tc superconducting power supply consists of two heater trigger and electric magnet, and YBCO superconducting bulk. In this experiment, 0.6T class magnet and dc 2.3A heater current are used, and the current-pumping characteristics have been analyzed with computer aided sequence control system. Hall sensors are installed on the YBCO bulk and in the center of iron core in order to analyze the effect of the flux-pumping on the system with when magnet flux changes its value. In this experiment, maximum pumping-current has been achieved to about 6.6 amps.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2210-2211
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• 2008

In this paper, we investigated the quenching characteristics of a superconducting fault current limiter (SFCL) with connection of $2{\times}3$ matrixes. This SFCL consists of the trigger part to apply magnetic field and the current-limiting part to limit the fault current. When the fault occurs, the magnetic field generated in the reactor connected in parallel was applied to the two superconducting units of the current-limiting part to reduce of inhomogeneous critical current behavior between the superconducting units. The quenching behavior of a superconducting unit in the trigger part was affected by the increase of turn numbers. This is because of the difference of current distribution between the inductance of the reactors and the resistance generated in the superconducting units in trigger part. We confirmed that the voltage differences between two superconducting units of the current-limiting part were decreased. This is because of the improvement of inhomogeneous critical current behavior between the superconducting units according to the increase of external magnetic field.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.4
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• pp.42-50
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• 2003

This paper presents an embedded RC oscillator which has temperature compensation circuits. The conventional RC oscillator has frequency deviation about 15%, which is caused by variation of resistors and the reference voltage of schmitt trigger from the temperature condition. In this paper, the proposed circuit use a CMOS bandgap reference having balanced current temperature coefficients as a triggering voltage of schmitt trigger. The constant current sources consist of current mirror circuit with the positive and negative temperature coefficient. The proposed circuit shows less 3% frequency deviation for variation of temperature, supply voltage and process parameters.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.7
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• pp.359-364
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• 2000

This paper is introducing a newly developed spark-gap switch with dual trigger system, into which the current from the voltage source is injected along with the test sequence during the synthetic testing of high voltage circuit-breaker. The currently-used spark gap switch is narrow in operating range due to the use of the method of triggering energy being injected by single way. As a result, the frequent happening of misoperation has greatly reduced the test quality and test efficiency and has required the cost of maintenance excessively. In this study, accordingly, in order to basically remove these problems, another triggering system is installed to the opposite direction on the existing triggering system; attaching the same time and the same rising time of pulse wave as on the existing system, so that at a comparatively trigger gap distance from the main electrode(the gap can be operated at 60% of self-break voltage, while at 80% in the current system), the main electrode has been enabled to be closed by the development of spark gap switch with dual trigger system.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.228.2-228.2
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• 2016

The triggered vacuum switch (TVS) discharges high current through two processes. In the first process, an igniting plasma is generated at a trigger system, and the next process that a main discharge is taken place sequentially at a six-gap rod electrode within a few microsecond. In general, a triggered voltage producing the igniting plasma is increased. However, after several hundred shots, it goes down and stable, in our experiment the trigger voltage is about 5 kV after 250 shots. This triggered characteristics comes from the ceramic insulator which is covered by an electrode material, therefore we have focused on the first igniting plasma process. The igniting plasma has been generated at the surface of a ceramic insulator under a strong electric field. The electric field can be increased through modifying geometries of trigger components which compose of a trigger pin, a ceramic insulator and an enclosed holder. We fabricated not only two types of trigger pin which are a plane head and an umbrella head type, but two different holders which are a concave and a convex type. In this paper the result that the dependency of geometries for these four combined types is included, but the study of the ceramic insulator is not. The research of the ceramic insulator will be announced in the other paper.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.2039-2040
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• 2006

Persistent current switch (PCS) system in NMR, MRI, MAGLEV and SMES has many advantages, such as uniformity and durability of magnetic field and reducing a thermal loss, which enable many superconducting application to operate effectively. This paper deals with fabrication and test of heater trigger persistent current switch using coated conductor (CC) which has high n-index, critical current independency from external magnetic field and adaptable selectivity of stabilizer. PCS system consists of magnet power supply for energizing current to a magnet, heater, switch and magnet using coated conductor tape. Finite element method (FEM) is used to simulate thermal quench (switching) characteristic and design heater trigger. With FEM simulation, optimal length of heater is calculated by temperature and time analysis. Fabrication of PCS system and test of heater trigger characteristic were performed and compared with simulation result. This paper would be the foundation of researches of superconducting switching application.

• Journal of Sensor Science and Technology
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• v.24 no.6
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• pp.398-403
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• 2015

In this paper, the sine-wave and trigger pulse generator with capability of frequency high-resolution and time-variable trigger edge has implemented. It fulfills well the requirements for SS-OCT with frequency resolution of 1 Hz, frequency stability of ${\leq}{\pm}0.03Hz$ and time-variable trigger edge. Through its performance test applied to the wavelength swept laser, 90 nm, sweeping range and 10mW average optical power were obtained. This showes that the realized generator can replace the commercial high cost and high performance signal generators employed by current SS-OCT systems.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.4
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• pp.549-553
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• 2018

The applications of the pulse power technology are expanding and the necessity of a large current switch as a core component of pulsed power is increasing. A trigger gap switch composed of three electrodes was fabricated and the discharge characteristics were studied according to the change of the pressure, the shape of the main electrode, and the gap distance when the trigger pulse was applied. As a main result, the stable operation range was confirmed through the discharge inception voltage according to the gap distance and electric field analysis was performed in the same structure to confirm the electric field value of the discharge inception voltage.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.142-144
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• 1989

Triggering characteristics of a trigatron spark gap have been studied by measuring self-emission UV light. By combining the measurement of the UV light with that of the trigger gap voltage and the lain discharge current, we distinguished clearly the differences between the trigatron operations in which the lain discharge occurs after the trigger discharge in the case of sale polarity between the trigger pin and the lain electrode at the opposite side, and the lain gap breakdown takes place before the formation of the trigger spark in the case of different polarity. We show the observation of UV radiation with the other electromagnetic measurements is a simple and reliable scheme to investigate the triggering properties of the trigatron spark gaps.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.7 s.361
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• pp.31-36
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• 2007

A saw-tooth waveform generator whose frequency can be controlled with a do bias current is proposed. The generator utilizes operational transconductance amplifiers (OTA's) as switching element. It features simple and wide sweep capability The circuit built with commercially avaliable components exhibits good linearity of current-to-frequency transfer characteristics and relatively low temperature sensitivity.