eCircuit Center ABCelectronique, portail de l'électronique Mike's Electric Stuff Circuit Simulator Applet This is an electronic circuit simulator. When the applet starts up you will see an animated schematic of a simple LRC circuit. The green color indicates positive voltage. To turn a switch on or off, just click on it. The "Circuits" menu contains a lot of sample circuits for you to try. Full Screen version. Directions. Standalone (offline) versions. Index of Circuit Examples. Réalisations - Alim. led Electronique > Réalisations > Alimentations > Alimentation d'une LED Dernière mise à jour : 06/03/2016 Présentation Les lignes qui suivent décrivent comment utiliser une LED de façon isolée ou en groupe, avec des tensions alternatives ou continues. Pour plus de renseignements concernant ce composant, merci de vous reporter à la page Théorie - LED. Bases - Alimentation en basse tension continue Une LED, si on l'alimente directement et sans autre forme de procès à une source de tension continue (pile 9 V neuve par exemple) ou à une source de tension alternative (secondaire d'un transformateur 220V / 9V par exemple), a 99% de chances de griller. Sur le schéma qui précède, la valeur de la résistance R1 est donnée à titre indicatif, la tension V n'étant pas spécifiée. La LED utilisée pour les deux expériences qui suivent est une LED verte fonctionnant de façon nominale avec une tension de 2,2 V et un courant de 20 mA. Valeurs typiques de tensions et courants pour quelques LED Remarques Oulà !
Electronic Circuits on Circuit Exchange International (CXI) Jones on Stepping Motor Types - Мозилин фајерфокс (Mozilla Firefox) Introduction Stepping motors come in two varieties, permanent magnet and variable reluctance (there are also hybrid motors, which are indistinguishable from permanent magnet motors from the controller's point of view). Lacking a label on the motor, you can generally tell the two apart by feel when no power is applied. Stepping motors come in a wide range of angular resolution. For both permanent magnet and variable reluctance stepping motors, if just one winding of the motor is energised, the rotor (under no load) will snap to a fixed angle and then hold that angle until the torque exceeds the holding torque of the motor, at which point, the rotor will turn, trying to hold at each successive equilibrium point. Variable Reluctance Motors Figure 1.1 The cross section shown in Figure 1.1 is of 30 degree per step variable reluctance motor. To rotate this motor continuously, we just apply power to the 3 windings in sequence. Unipolar Motors Figure 1.2 Bipolar Motors Figure 1.3 Bifilar Motors
Motors and Microcontrollers 101 Electric motors are a key way of converting electrical power (voltage and current) into mechanical power (torque and speed), and because electric motors are simple and reliable machines, they can be found all over, in many different shapes and sizes. Just considering a normal (gasoline-powered) car, there are a great number of electric motors: the powerful starter motor and alternatoralternating windshield wiper motorsintermittent-use power windows and door locksthe blower fan that moves hot and cold air into the cabinthe tiny motors inside the CD player And I'm sure you can think of others. While a full analysis would have to look simultaneously at the motor and the attached mechanical system, in this video tutorial we're just going to address the electrical side of the system. Here are some photos and drawings related to the video (click to enlarge): Our final motor control circuit looks like this: Spinning the motor makes a voltage. Go give them a try! Maximum forward current.
Bipolar junction transistors as switches : Worksheet Question 1: Solid-state switching circuits usually keep their constituent transistors in one of two modes: cutoff or saturation. Explain what each of these terms means. "Cutoff" refers to that condition where a transistor is not conducting any collector current (it is fully off). "Saturation" means that condition where a transistor is conducting maximum collector current (fully on). Notes: In all fairness, not all transistor switching circuits operate between these two extreme states. Question 2: Explain the function of this light-switching circuit, tracing the directions of all currents when the switch closes: Notes: Ask your students to explain what possible purpose such a circuit could perform. Question 3: Trace the directions of all currents in this circuit, and determine which current is larger: the current through resistor R1 or the current through resistor R2, assuming equal resistor values. I'll let you determine the directions of all currents in this circuit! Question 4: Question 5:
Soldermans Basic Electronics: Binary and Hex - Мозилин фајерфокс (Mozilla Firefox) Computers understand numbers and logic, as most are digital computers. The Binary Hexadecimal System is the way the numbers or logical commands are instructed to the computer. All input devices or sensors must finally talk this language to the CPU, and all outputs and actuators must be able to understand this numbers to do their job. A bimetallic thermostat is like a simple mechanical computer. Where the bimetal response is the sensor input, the contacts are the output to actuator and the bimetal thermal behavior is of the nature of intelligence. Bit is 0 or 1 ... one digit ... 0 could be 0 volts and 1 five volts.Nibble is four bits, 4 digits, like 0010 , in hex a nibble is 0 to F.Byte is eight bits, 8 digits, like 1100 0010 , in hex 00 to FF.BCD binary coded decimal is binary code for numbers 0 to 9.Learn more by reading asciicat here.
b e a . s t [an error occurred while processing this directive] Magnetic Levitation using Hall effect Sensor Feedback, and Matched resonant wireless power transfer This work was completed initially for a final project for Joe Paradiso's class MAS.836 - Sensor systems for Interactive Environments, taken Spring 2oo5. Click to watch the following movies:Magnet Levitation Movie [100 megs], or in Small form. Motivation: My goal is to build the subsystems to be able to magnetically [stably] levitate a lightbulb that is powered at all times through the air using a matched resonant air-core transformer. In order to levitate a lightbulb, there are three main systems that needed to be explored and techniques that needed to be developed. Implementation: The general goal setup is as shown to the right. Around the electromagnet sits another coil, the primary of an air-core resonant transformer; the secondary winding sits near the neodymium magnets inside the light bulb. Hall Effect Sensing: One problem remains.
pH measurement : ELECTRICAL INSTRUMENTATION SIGNALS A very important measurement in many liquid chemical processes (industrial, pharmaceutical, manufacturing, food production, etc.) is that of pH: the measurement of hydrogen ion concentration in a liquid solution. A solution with a low pH value is called an "acid," while one with a high pH is called a "caustic." The common pH scale extends from 0 (strong acid) to 14 (strong caustic), with 7 in the middle representing pure water (neutral): pH is defined as follows: the lower-case letter "p" in pH stands for the negative common (base ten) logarithm, while the upper-case letter "H" stands for the element hydrogen. The logarithmic pH scale works like this: a solution with 10-12 moles of H+ ions per liter has a pH of 12; a solution with 10-3 moles of H+ ions per liter has a pH of 3. The design and operational theory of pH electrodes is a very complex subject, explored only briefly here. Here is an illustration of the measurement electrode's construction.
Tutorials The most fun you can have (after blinking LEDs) is using sensors to detect whats going on in the world and act on that information. However, all sensors have their own methods of interfacing. That can make them a real pain to work with: some need pull-up resistors, some need certain power supplies, some use lots of power, some don't. Since there aren't that many different sensors that people tend to want to use I have collected the most common sensors with code examples and wiring diagrams. Tutorials include: Force sensitive resistor - Used to detect physical pressure such as pinching, squeezing, pushing, brushing. Photocells - Used to detect light/dark, breakbeams, simple object detection.