Audio-Light Modulator Isolator

his electronc circuit uses an Optocoupler Triac, MOC3010. Provides for complete electrical isolation between an input signal (audio) whch is a low voltage circuit and the output light modulation. The circuit operates on a main AC voltage of 120V AC. The input audio connector is a 3.5mm jack - the same as an ipod or other headphone.Specifications:

• L: 2-1/8" W: 1-5/8" H: 1-5/8"
• Requires 110 VAC
• Input Trigger Voltage 2.3V minimum
• Load Max 500W @ 250V, 220W @ 110V

Alternating Flashing LED's / Lights - One LED ON, One OFF

Topics: LED Circuits

Create alternating flashing LED's with this 555 timer based LED flashing circuit. Perfect for warning sign or model railroad crossing signal.

This small and simple electronic circuit behaves like the flash lights that you see at dangerous corners where your driving or at a railroad. i.e. it has two LED's / lights that flashes in an alternating fashion. You can use any color LED's e.g. red LED's, green, LED's, yellow, orange, etc.
The circuit has only 6 components, and that's including the 2 LED's. The main part of the circuit is the venerable 555 timer IC. Is there any timing circuit that doesn't use the 555?
Components:

• 1 x 555 Timer IC
• 1 x 33k Resistor
• 1 x 120k Resistor
• 1 x 1 µF (micro-Farad) Capacitor
• 2 x LED

Anyway... this is perfect if you want to experiment with the 555 timer, build a warning signal for a model railroad, or, well.... just about anything else that might required alternating flashing LED's
Happy soldering!!!

FM TRANSMITER 3Vdc

FM TRANSMITER 3Vdc

powerful FM Transmitter circuit we've seen that operates on such low voltage (just two AA cells). A range of 200 ft can be expected and, given a good antenna and FM receiver, over 1/4 mile can be expected. An external power supply can be used up to 9 volts. Transmits to the FM radio band, which means you can use any FM radio to receive the transmitter. Teaches basics of FM transmitters. Microphone is included.
Specifications:

• L: 1-3/4" W: 3/4" H: 1/2"
• Requires 2 AA batteries (holder included, not shown in pic.) 9 volt battery can be used to increase range.
• FM Transmitter frequency is user selectable.
• Transmitter can be listened to on any FM radio.

BIPOLAR TRANSISTOR FOR THE RF OF IC DESIGN.

BIPOLAR TRANSISTOR FOR THE RF OF IC DESIGN.

A scalable model generation methodology for
bipolar transistors is presented. The methodology is
efficient in generating extensive model libraries for
RFIC design. Experimental results for a production
RF BiCMOS process are provided, confirming the
quality of the model library generated with the
methodology. Finally, an example of first-pass design
success enabled by this methodology is presented,
demonstrating the usefulness of the modeling
methodology for RF IC design.
Acknowledgement
The authors are especially thankful to the RFIC
Design Group and the Advanced Process Technology
(APT) Development within Conexant for their support.
References
[1] M. Schroter et al., “Physics- and process-based
bipolar transistor modeling for integrated circuit
design”, IEEE Journal of Solid-State Circuits, Vol. 34,
pp. 1136-1149, 1999.
[2] T.-Y. Lee and M. Schroter, “Methodology for Bipolar
Compact Model Parameter Extraction”, CMC
Meeting, Sept. 29, www.eigroup.org/cmc, 1999.
[3] H. Tran et al., “Simultaneous extraction of thermal
and emitter series resistance in bipolar
transistors”, Proc. BCTM, pp. 170-173, 1997.
[4] R. Gabl, M. Reisch, and M. Pohl, “Improved
extraction method for the emitter resistance of
bipolar transistors”, Proc. BCTM, pp. 211-214,1998.
[5] M. Schroter and T.-Y. Lee, “Physical-based Minority
Charge and Transit Time Modeling for Bipolar
Transistors”, IEEE Trans. Electron. Dev., Vol. 46, pp.
288-300, 1999.
[6] M. Racanelli et al., “BC35: a 0.35 μm, 30GHz,
Production RF BiCMOS Technology”, Proc. BCTM,
pp. 125-128, 1999.
[7] M. Schroter, D.R. Pehlke, and T.-Y. Lee, “Compact
Modeling of High-frequency Distortion in Bipolar
Transistors”, IEEE Trans. Electron. Dev., pp. 1529-
1539, 2000.

SILICON CONTROLED RECTIFIER

SILICON CONTROLED RECTIFIER
From Tono Maryono in Garut.

A silicon-controlled rectifier (or semiconductor-controlled rectifier) is a four-layer solid state device that controls current. The name "silicon controlled rectifier" or SCR is General Electric's trade name for a type of thyristor. The SCR was developed by a team of power engineers led by Gordon Hall and commercialized by Frank W. "Bill" Gutzwiller in 1957.

Construction of SCR

An SCR consists of four layers of alternating P and N type semiconductor materials. Silicon is used as the intrinsic semiconductor, to which the proper dopants are added. The junctions are either diffused or alloyed. The planar construction is used for low power SCRs (and all the junctions are diffused). The mesa type construction is used for high power SCRs. In this case, junction J2 is obtained by the diffusion method and then the outer two layers are alloyed to it, since the PNPN pellet is required to handle large currents. It is properly braced with tungsten or molybdenum plates to provide greater mechanical strength. One of these plates is hard soldered to a copper stud, which is threaded for attachment of heat sink. The doping of PNPN will depend on the application of SCR, since its characteristics are similar to those of the thyratron. Today, the term thyristor applies to the larger family of multilayer devices that exhibit bistable state-change behaviour, that is, switching either ON or OFF.

The operation of a SCR and other thyristors can be understood in terms of a pair of tightly coupled bipolar junction transistors, arranged to cause the self-latching action: