The current produced in a circuit by a DC voltage is directly proportional to the DC voltage. The constant of proportionality is resistance, R which is a property of matter and resistor demensions.
V = IR
Ohms Low Demonstration
for I =V/R
Monday, October 26, 2009
Matter and Electricity
Force Fields: A Physics E&M Primer for Electronic Students. This free physics eBook teaches the basics of electricity and Magnetism. Electricity is a physical phenomena involving positive and negative charge. When these charges are in motion they may produce heat, light and magnetism. When charges are not in motion, static electricity can manifests itself as a force such as clothes clinging to each other when they are removed from a dryer. A simple stationary system of a single positive ion and a single negative ion (or electron) separated by large distance with respect to their size ( a meter for example) will have a E field associated with them. Along the axis connecting the two ions the E vector points directly from the positive ion towards the negative ion. At this theoretical point in time there is no H field. The E field will cause the charge particles to move towards each other. This relative motion of positive and negative charge is the simplest example of current. Associated with this tiny current a magnetic or H field will exist. The motion of the positive charge will be in the direction of the E field and the negative charge will move in the opposite direction of the E field. Current by definition flows in the direction of the E field. It follows that positive charge moves in the direction of current and negative charge moves opposite to the current. Practical Application of above: When I studied electronics in the military, I learned the electron flow version of electronics. When I studied Physics in college, we used conventional current flow. This made remembering things like the left hand rule and right rules for curl etc. very confusing. Thus, I recommend not buying an electron flow version of a text and sticking with conventional current flow. |
Thursday, October 22, 2009
Battery Management
Battery Management
New high-frequency switch-mode Li-Ion battery charger simplifies constant current control in quick-charge portables. The ADP2291 is a constant-current/constant-voltage linear charger for a single cell lithium ion battery, requiring just a few components to provide a simple and safe charging system that operates from a wide 4.5V to 12V input voltage range. The industry’s highest end-of-voltage accuracy levels are achieved to within ±0.4% at 25ºC, ±0.6% at 5ºC to 55ºC and ±0.7% at 0ºC to 85ºC.
New high-frequency switch-mode Li-Ion battery charger simplifies constant current control in quick-charge portables. The ADP2291 is a constant-current/constant-voltage linear charger for a single cell lithium ion battery, requiring just a few components to provide a simple and safe charging system that operates from a wide 4.5V to 12V input voltage range. The industry’s highest end-of-voltage accuracy levels are achieved to within ±0.4% at 25ºC, ±0.6% at 5ºC to 55ºC and ±0.7% at 0ºC to 85ºC.
Digital Temperature Sensors
Digital Temperature Sensors
ADI has a broad selection of digital temperature sensors with I2C, SPI and mark-space interfaces. For more intricate system design applications, some of these digital temperature sensors have integrated DACs, ADCs, references, and limit alarm registers. All these digital temperature sensors has the diversity to be used in a broad range of applications.
ADI has a broad selection of digital temperature sensors with I2C, SPI and mark-space interfaces. For more intricate system design applications, some of these digital temperature sensors have integrated DACs, ADCs, references, and limit alarm registers. All these digital temperature sensors has the diversity to be used in a broad range of applications.
Analog Temperature Sensors
Analog Temperature Sensors
ADI offers a complete range of analog and digital temperature sensors. Choose one of ADI's analog temperature sensors if a simple voltage or current out function is required. Unlike traditional conventional methods, these analog sensors eliminate the need for trimming, buffering, and linearization. This saves on both cost and unnecessary circuit design. ADI also has a selection of high accurate, low cost digital temperature sensors with I2C, SPI, mark-space, and trip-point interfaces. For more intricate system design applications, some of these digital temperature sensors have integrated DACs, ADCs, references, and limit alarm registers. This complete family of temperature sensors has the diversity to be used in a broad range of applications.
ADI offers a complete range of analog and digital temperature sensors. Choose one of ADI's analog temperature sensors if a simple voltage or current out function is required. Unlike traditional conventional methods, these analog sensors eliminate the need for trimming, buffering, and linearization. This saves on both cost and unnecessary circuit design. ADI also has a selection of high accurate, low cost digital temperature sensors with I2C, SPI, mark-space, and trip-point interfaces. For more intricate system design applications, some of these digital temperature sensors have integrated DACs, ADCs, references, and limit alarm registers. This complete family of temperature sensors has the diversity to be used in a broad range of applications.
Laser Drivers
Laser Drivers
ADI’s laser diode driver ICs support data rates from 50Mbps to 10.7Gbps used by Fabry-Perot, DFB and Vcsel lasers. Module MSAs, such as SFP with SFF-8472 Digital Diagnostics, SFF, 4X Fiber Channel, XFP, Xenpak, X2 and MSA-300, are also supported. Featuring automatic dual-loop control of extinction ratio and average power, temperature calibration is not required to compensate for laser aging and degradation. This lowers TOSA and module costs.
ADI’s laser diode driver ICs support data rates from 50Mbps to 10.7Gbps used by Fabry-Perot, DFB and Vcsel lasers. Module MSAs, such as SFP with SFF-8472 Digital Diagnostics, SFF, 4X Fiber Channel, XFP, Xenpak, X2 and MSA-300, are also supported. Featuring automatic dual-loop control of extinction ratio and average power, temperature calibration is not required to compensate for laser aging and degradation. This lowers TOSA and module costs.
CATV Amps/Splitters
CATV Amps/Splitters
Cable modems and CATV set-top boxes are comprised of mostly digital components, but high performance analog circuitry is still critical to the application. Analog Devices continues to be a major supplier for this need with its portfolio of CATV line drivers and active RF splitters. ADI's high performance drivers and splitters enable the implementation of the most advanced cable modems and set top boxes on the market.
Cable modems and CATV set-top boxes are comprised of mostly digital components, but high performance analog circuitry is still critical to the application. Analog Devices continues to be a major supplier for this need with its portfolio of CATV line drivers and active RF splitters. ADI's high performance drivers and splitters enable the implementation of the most advanced cable modems and set top boxes on the market.
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