Tag Archives: Transistor

Simple crystal tester

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Dilshan Jayakody build a simple crystal tester based on Colpitts oscillator. He writes:

This is simple Colpitts oscillator to test commonly available passive crystals which range between 2MHz to 27MHz. This unit must connect to an oscilloscope and/or frequency counter to get the frequency of the crystal. This circuit is design to work around 9V to 12V DC power source. Both 2SC930 transistors can replace with any high speed NPN transistor such as 2SC829, 2SC933, etc.

Simple crystal tester – [Link]

USB curve tracer for NPN transistors

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Dilshan Jayakody documented his USB port base NPN transistor curve tracer project:

Curve tracer is an electronic test instrument to analyze the characteristics of transistors and other discrete semiconductors. In this post we construct USB base curve tracer to analyze properties of NPN transistors. This curve tracer is build around Microchip’s PIC18F4550 MCU and it use simple Windows based GUI application to plot captured data of a transistor.

USB curve tracer for NPN transistors – [Link]

Record-setting flexible phototransistor revealed

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Researchers at the University of Wisconsin-Madison have revealed a unique phototransistor that is flexible and faster and more responsive than any similar phototransistor.

The innovative phototransistor could improve the performance of myriad products — ranging from digital cameras, night-vision goggles and smoke detectors to surveillance systems and satellites — that rely on electronic light sensors. Integrated into a digital camera lens, for example, it could reduce bulkiness and boost both the acquisition speed and quality of video or still photos.

Record-setting flexible phototransistor revealed – [Link]

Power ON Delay Switch

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Power-ON Delay Switch which can be used in all applications requiring a delay during power-on from 1 to 60 seconds.

Specifications

  • Supply input 5 VDC
  • Relay output SPDT relay
  • Relay specification 5 A @ 250 VAC
  • Preset adjustable range function
  • Power-On LED indicator
  • Screw terminal connector for easy relay output connection
  • Four mounting holes of 3.2 mm each
  • PCB dimensions 44 mm x 42 mm

Power ON Delay Switch – [Link]

Component Tester FISH 8840 Review

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Alan Parekh @ hackedgadgets.com has a review of a cheap component tested he found on ebay. This device can test bipolar transistors, MOSFET, diodes, thyristors, resistors and capacitors. He writes:

This is an inexpensive component tester called the FISH 8840 which you can find from many online eBay retailers for around $30. The interface is very simple, attach a device to be tested and press the test button. It turns off after about 20 seconds, pressing the off button puts it into sleep mode immediately. There is a ZIF socket that allows you to insert leaded devices and pads that allow you to press SMD devices directly onto the tester.

Component Tester FISH 8840 Review – [Link]

New flat transistor defies theoretical limit

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by Bob Yirka @ techxplore.com:

A team of researchers with members from the University of California and Rice University has found a way to get a flat transistor to defy theoretical limitations on Field Effect Transistors (FETs). In their paper published in the journal Nature, the team describes their work and why they believe it could lead to consumer devices that have both smaller electronics and longer battery life. Katsuhiro Tomioka with Erasmus MC University Medical Center in the Netherlands offers a News & Views article discussing the work done by the team in the same journal edition.

New flat transistor defies theoretical limit – [Link]

[Article] Basic Transistor Types

In this article we will review the basic transistor types and their function. We will cover bipolar transistor, Junction FET, MOSFET and UJT transistor types. Feel free to comment with other transistor types you know.

Bipolar Transistor

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Bipolar transistors are three terminal devices and act like electrically controlled switches of as current/voltage amplifiers. They come in two types either npn or pnp depending on their construction.

NPN Transistor

This type of transistor is normally off, but a small input current and a small positive voltage to its base B (relative to emitter – E) allows a large current to flow from collector to emitter, when collector is in higher voltage than emitter. Normally used in switching applications and amplifiers.

PNP Transistor

This type of transistor is normally off, but a small output current and a small negative voltage to its base B (relative to emitter – E) allows a large current to flow from emitter to collector, when emitter is in higher voltage than collector. Normally used in switching applications and amplifiers.

Junction FET

JFET

Junction field effect transistors are three terminal devices that are used as switches, amplifiers or voltage controlled resistors. Unlike bipolar transistors they don’t require a biasing current just a voltage to the gate to operate. Another difference with bipolar is that they are normally ON without any voltage to the gate.

n-channel JFET

This type of transistor in normally ON and a small negative voltage to it’s gate – G (related to source – S) stops the large current that flows from drain to source, when voltage of drain is greater than voltage on source. A unique feature is that they don’t need a current to it’s gate and are used in switching and amplifying applications.

p-channel JFET

This type of transistor in normally ON and a small positive voltage to it’s gate – G (related to source – S) stops the large current that flows from drain to source, when voltage of source is greater than voltage on drain. They also don’t need a current to it’s gate and are used in switching and amplifying applications.

Depletion MOSFET

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Metal oxide semiconductor field effect transistors or MOSFETs is a popular type of transistors and when a small voltage is applied to its gate the current flow from Drain to Source is stopped. In contrast to JFETs, MOSFETs have larger input impedance and they draw virtually no current on their gate. There are two main type of depletion MOSFETs, n-channel and p-channel.

n-channel depletion MOSFET

N-channel depletion MOSFETs are normally ON, but a small negative voltage to the gate (related to source – S) stops the current flow from drain to source, when voltage on drain is greater than voltage on source. They need no current at all to the gate.

p-channel depletion MOSFET

P-channel depletion MOSFETs are normally ON, but a small positive voltage to the gate (related to source – S) stops the current flow from source to drain, when voltage on source is greater than voltage on drain. They need no current at all to the gate.

Enhancement MOSFET

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n-channel enhancement MOSFET

N-channel enhancement MOSFETs are normally OFF, but a small positive voltage to the gate (related to source – S) allows current to flow from drain to source, when voltage on drain is greater than voltage on source. They need no current at all to the gate.

p-channel enhancement MOSFET

P-channel enhancement MOSFETs are normally OFF, but a small negative voltage to the gate (related to source – S) allows current to flow from source to drain, when voltage on source is greater than voltage on drain. They need no current at all to the gate.

Unijunction FET (UJT)

UJT

Unijunction transistors (UJTs) are three terminal devices that are used exclusively as switches and not as amplifiers. Normally a very small current flows from B2 to B1 but if a large positive voltage is applied to emitter – E (related to B1 or B2) increases the current flow, when voltage from B2 is greater than voltage on B1. The larger current from E combines with the smaller current from B2 to B1, thus giving a large current in B1. In this type of transistor the emitter current is the main source of current passing through B2-B1.

Build an op amp with three discrete transistors

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by Lyle Russell Williams:

You can use three discrete transistors to build an operational amplifier with an open-loop gain greater than 1 million (Figure 1). You bias the output at approximately one-half the supply voltage using the combined voltage drops across zener diode D1, the emitter-base voltage of input transistor Q1, and the 1V drop across 1-MΩ feedback resistor R2.

Build an op amp with three discrete transistors – [Link]

650V, 100A GaN transistors on show

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by Graham Prophet @ edn-europe.com:

GaN Systems (Ottawa, Canada) is to display its GS66540C 650V 100A high current GaN power transistors for the first time at the 17th Conference on Power Electronics and Applications, EPE’15 – ECCE Europe (CERN, Geneva, September 8th – 10th )

The GS66540C (the picture is of a prior, lower-current part) high current power devices will be revealed for the first time. Part of the company’s family of 650V gallium nitride power transistors based on its proprietary Island Technology, these high density devices achieve extremely efficient power conversion with fast switching rates of >100V/nsec and ultra-low thermal losses. The GS66540C is supplied in an evolved form of GaNPX packaging specially developed for higher operating currents, providing lower inductance and greater surface mount mechanical robustness required by power modules for the industrial and automotive markets. The near-chipscale parts have no wirebonds and offer step-change improvements in switching and conduction performance over traditional silicon MOSFETs and IGBTs. Parts are, the company says, being designed in to solar, industrial and automotive applications as global manufacturers race to use the power of GaN to secure competitive advantage.

650V, 100A GaN transistors on show – [Link]

Terahertz Optical Transistors Beat Silicon

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by R. Colin Johnson @ eetimes.com:

PORTLAND, Ore.–Purdue University researchers have demonstrated a CMOS-compatible all-optical transistor capable of 4THz speeds, potentially over a 1000 times faster than silicon transistors.

Nano-photonic transistors processed at low-temperatures can be fabricated atop complementary metal oxide semiconductors (CMOS) to boost switching time by ~5,000-times less than 300 femtoseconds (fs) or almost 4 terahertz (THz), according to researchers at Purdue University. The aluminum-doped zinc oxide (AZO) material from which these optical transistors are fabricated has a tunable dielectric permittivity compatible with all telecommunications infrared (IR) standards.

Terahertz Optical Transistors Beat Silicon – [Link]