Electronics-Lab.com Blog

www.changpuak.ch writes:

The Approach used here is just an active Voltage Divider. The GND of the Output just has to be centered between the positive and the negative Supply. This can be achieved using a Power Opamp such as the L149 (4A) or the L165 (3A) or any
equivalent type beeing available at your local hardware store. The Schematics below shows how to wire it …

How to transform an Unipolar Power Supply into a Bipolar Power Supply - [Link]

PCB terminal blocks series MVS15x-IT from Euroclamp provide an added value in the form of an easy connection of wire leads even in tight conditions. Thanks to a construction slanted in 35°, they fit exactly into conditions, where horizontal, neither vertical terminal blocks aren´t the right solution.

A relatively common situation – a construction of your device doesn´t allow you to use vertical terminal blocks and at horizontal ones you face the problem with components placed too close to a terminal block, thus preventing a proper installation of wire leads.

MVS15x-IT series slanted in 35° is the solution for such and many other cases. Available are versions with 5mm as well as 10mm pin spacing. Types with a 5mm pitch can be found in our standard stock offer. Basic components are 2 and 3-pole terminal blocks MVS152-5-IT and MVS153-5-IT. Also available is the MVS1510-5-IT, representing a price convenient alternative, when you need to create a row with 10 and more poles. Terminal blocks are made from PA (polyamide) UL94-V0 class, nickel-plated copper alloy and the screw is from a galvanized steel. Detailed information will provide you datasheets at respective types.

Neither horizontal, nor vertical – slant terminal blocks are the right ones! - [Link]

image source: www.tradeofic.com

The need for high capacitance can be fulfilled via the use of a Capacitance Multiplier. The operational amplifier circuit is used as a capacitance multiplier in such a way that multiple small physical capacitances are combined in the integrated circuit technology to yield a large overall capacitance. The aim is often to multiply the original capacitance value hundreds and thousands of times. For example, a capacitor of 10 pF capacitance could be upgraded by the use of capacitance multiplier to behave like a 100 nF capacitor.

Construction of Capacitance Multiplier Circuits:

The circuit construction of a capacitance multiplier is quite simple. Two operational amplifiers, two resistors and a capacitor are used. The second operational amplifier is an inverted amplifier. A voltage source connected to the first operational amplifier will make the amplifier operate as a voltage follower. The circuit will produce a capacitance via the load imposition created by the second amplifier acting as an inverted amplifier. The produced capacitance is isolated from the circuit with the help of voltage follower. In this way, no current flows into the input terminals of the operational amplifier – the input current will flow through the feedback capacitor of the capacitance multiplier circuit.

How Are Multiple Capacitances Produced Using An Operational Amplifier Circuit?

Critical to production of effective capacitance is the selection of good resistance values for the two resistors in the multiplier circuit. The effective capacitance produced will be the capacitance between the input terminal of the operational amplifier and the ground. This effective capacitance will be the multiple of the physical capacitance ‘C’ of the operational amplifier circuit being used as a capacitance multiplier. There is an option to limit the size of this effective capacitance by the use of an inverted output voltage limitation technique. This is a practical approach to limit the size of the effective capacitance.

Relation between Size of Effective Capacitance and Input Voltage:

The capacitance multiplication and the maximum input voltage avoiding saturation state in the operational amplifier are inversely proportional to one other. Effectively, the larger the size of the effective capacitance, the smaller the input voltage into the input terminals of the operational amplifier. Using a similar technique, a resistance multiplier circuit can also be implemented by configuring an operational amplifier circuit. Furthermore, the same operational amplifier circuit can also be designed to simulate inductance.

TPS7A7100 LDO Regulator

The TPS7A7100/200/300 low-dropout (LDO) voltage regulators are designed for applications seeking very low dropout capability (typically less than 100mV at 1-A load) with an input voltage from 1.5V to 6.5V. The TPS7A7100 offers an innovative, user-configurable output-voltage setting from 0.9V to 3.5V. The output is pin-programmable, which eliminates accuracy error due to the tolerance of feedback resistors used in traditional adjustable regulator designs.

Very Low Input – Programmable Output (0.9V to 5.0V) Low-Dropout Linear Regulators - [Link]

Automotive relay for PCB used by leading car companies was introduced to you in a recent article. Moreover, now you can buy this relay for a substantially lower price.

Relay V23084-C2001-A303, marked also as 1393267-2 is a well-proven 12V miniature double relay with changeover contacts, which can be used for servicing as well as for new applications. During past months we registered your stable interest about this type of relay, that´s why we tried to negotiate even better purchase conditions.

We managed it and we want to pass this benefit to you. This enables us to offer the relay to you for a considerably lower price than so far. Detailed information will provide you our article “Automotive relay for PCB used by leading world producers” as well as the V23084-C2001-A303 datasheet. A lower price is valid till actual stock sell-out.

Automotive relay for the price like never before - [Link]

Modkit Micro is a graphical programming environment for microcontrollers.  Microcontrollers allow programmers and engineers to add behaviors to everyday objects and electronic gadgets.  We created Modkit Micro to bring the world of microcontroller programming to the masses.

Modkit Micro helps almost anyone to make almost anything smarter through a simple, yet powerful visual programming interface.  Modkit Micro is based on years of research at the MIT Media Lab including the popular Scratch project, so it will look familiar to the over 1 million kids and novice programmers who have already been introduced to Scratch.

Modkit Micro: The Easiest Way to Program Microcontrollers - [Link]

Mayhew Labs writes:

The Rotary Encoder LED Ring is a position indicator for rotary encoders. Traditional knobs with indicator lines do not give accurate representation of an encoder’s value since rotary encoders have no start or end point.

Rotary encoders are used as input devices in applications where a single encoder has many functions or where a control responds to the rotation rate of an encoder. In these applications, the Rotary Encoder LED Ring offers a visual representation of how an encoder is reacting to the input as well as the current position or control value.

Rotary Encoder LED Ring - [Link]

This is a simple use of internal ADC of AVR atmega8. Voltage is measured directly with help of resistor divider and amperes is calculated based on the voltage drop in a low resistance power resistor.

Atmega8 based Volt – Ampere meter - [Link]

Just a few rules:

1.  Add a comment on the thread http://community.openpicus.com/forum/projects-place/1194/contest-get-free-flyport-ethernet-easter describing the application you aim to create using Flyport Ethernet and Lighting nest.
2. The winner agrees to share with the entire project with the Community (source code, description, maybe a video or pictures)
3. The contest starts on 27th March 2012 and it ends on 5th of April 2012
4. openPICUS Team reserves the freedom to choose the application that it considers most interesting

Good Luck!

Flyport Ethernet is a miniature web server module featuring a fully integrated 10/100 Base-T ethernet interface and several interfaces to the ‘real world’. Flyport Ethernet integrates a 16 bit processor which runs custom applications and an Ethernet interface controller with integrated MAC & PHY, hardware cryptographic security and a unique MAC address. An RJ45 connector can be mounted on the module, or routed at external addons boards.

Flyport is powered by openPicus, an open source framework and serial booloader. The free openPicus IDE allows to create applications, to import web pages and to compile and download code to the module.

A Flyport Ethernet + 1 Lighting Nest + 1 miniUSB Programmer to the best project idea! - [Link]

A Wireless XBee Pan/Tilt Servo System For Cameras. It uses a pair of XBee modules to build a simple wireless interface which will be used with PIC 18LF4520′s to control a servo based pan and tilt system which can move my camera 45 degrees in any direction, left-right-forward-backwards.

Wireless XBee Pan/Tilt System - [Link]