Random access memory (RAM) is a form of computer data storage. Today, it takes the form of integrated circuits that allow stored data to be accessed in any order with a worst case performance of constant time. Strictly speaking, modern types of DRAM are therefore not random access, as data is read in bursts, although the name DRAM / RAM has stuck. However, many types of SRAM, ROM, OTP, and NOR flash are still random access even in a strict sense. RAM is often associated with volatile types of memory (such as DRAM memory modules), where its stored information is lost if the power is removed. Many other types of non-volatile memory are RAM as well, including most types of ROM and a type of flash memory called NOR-Flash. The first RAM modules to come into the market were created in 1951 and were sold until the late 1960s and early 1970s.Friday, March 23, 2012
RAM
Random access memory (RAM) is a form of computer data storage. Today, it takes the form of integrated circuits that allow stored data to be accessed in any order with a worst case performance of constant time. Strictly speaking, modern types of DRAM are therefore not random access, as data is read in bursts, although the name DRAM / RAM has stuck. However, many types of SRAM, ROM, OTP, and NOR flash are still random access even in a strict sense. RAM is often associated with volatile types of memory (such as DRAM memory modules), where its stored information is lost if the power is removed. Many other types of non-volatile memory are RAM as well, including most types of ROM and a type of flash memory called NOR-Flash. The first RAM modules to come into the market were created in 1951 and were sold until the late 1960s and early 1970s.
Sunday, March 18, 2012
ROM
Read-only memory (ROM) is a class of storage medium used in computers and other electronic devices. Data stored in ROM cannot be modified, or can be modified only slowly or with difficulty, so it is mainly used to distribute firmware (software that is very closely tied to specific hardware, and unlikely to need frequent updates).In its strictest sense, ROM refers only to mask ROM (the oldest type of solid state ROM), which is fabricated with the desired data permanently stored in it, and thus can never be modified. Despite the simplicity, speed and economies of scale of mask ROM, field-programmability often make reprogrammable memories more flexible and inexpensive. As of 2007[update], actual ROM circuitry is therefore mainly used for applications such as microcode, and similar structures, on various kinds of digital processors (i.e. not only CPUs).
Other types of non-volatile memory such as erasable programmable read only memory (EPROM) and electrically erasable programmable read-only memory (EEPROM or Flash ROM) are sometimes referred to, in an abbreviated way, as "read-only memory" (ROM), but this is actually a misnomer because these types of memory can be erased and re-programmed multiple times.[1] When used in this less precise way, "ROM" indicates a non-volatile memory which serves functions typically provided by mask ROM, such as storage of program code and nonvolatile data.
Friday, March 16, 2012
Wednesday, February 29, 2012
Timer IC 555
555 timer IC
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NE555 from Signetics in dual-in-line package
Internal block diagramIntroduced in 1971 by Signetics, the 555 is still in widespread use, thanks to its ease of use, low price and good stability, and is now made by many companies in the original bipolar and also in low-power CMOS types. As of 2003, it was estimated that 1 billion units are manufactured every year.
Design
The IC was designed in 1971 by Hans R. Camenzind under contract to Signetics, which was later acquired by Philips.Depending on the manufacturer, the standard 555 package includes 25 transistors, 2 diodes and 15 resistors on a silicon chip installed in an 8-pin mini dual-in-line package (DIP-8).Variants available include the 556 (a 14-pin DIP combining two 555s on one chip), and the two 558 & 559s (both a 16-pin DIP combining four slightly modified 555s with DIS & THR connected internally, and TR is falling edge sensitive instead of level sensitive). There is no 557.
The NE555 parts were commercial temperature range, 0 °C to +70 °C, and the SE555 part number designated the military temperature range, −55 °C to +125 °C. These were available in both high-reliability metal can (T package) and inexpensive epoxy plastic (V package) packages. Thus the full part numbers were NE555V, NE555T, SE555V, and SE555T. It has been hypothesized that the 555 got its name from the three 5 kΩ resistors used within, but Hans Camenzind has stated that the number was arbitrary.
Low-power versions of the 555 are also available, such as the 7555 and CMOS TLC555. The 7555 is designed to cause less supply glitching than the classic 555 and the manufacturer claims that it usually does not require a "control" capacitor and in many cases does not require a decoupling capacitor on the power supply. Such a practice should nevertheless be avoided, because noise produced by the timer or variation in power supply voltage might interfere with other parts of a circuit or influence its threshold voltages.
Monday, February 27, 2012
Autotransformer
An autotransformer is an electrical transformer with only one winding. The auto prefix refers to the single coil acting on itself rather than any automatic mechanism. In an autotransformer portions of the same winding act as both the primary and secondary. The winding has at least three taps
where electrical connections are made. An autotransformer can be
smaller, lighter and cheaper than a standard dual-winding transformer
however the autotransformer does not provide electrical isolation.
Autotransformers are often used to step up or down between voltages in the 110-117-120 volt range and voltages in the 220-230-240 volt range, e.g., to output either 110 or 120V (with taps) from 230V input, allowing equipment from a 100 or 120V region to be used in a 230V region.
One end of the winding is usually connected in common to both the voltage source and the electrical load.
The other end of the source and load are connected to taps along the
winding. Different taps on the winding correspond to different voltages,
measured from the common end. In a step-down transformer the source is
usually connected across the entire winding while the load is connected
by a tap across only a portion of the winding. In a step-up transformer,
conversely, the load is attached across the full winding while the
source is connected to a tap across a portion of the winding.
As in a two-winding transformer, the ratio of secondary to primary voltages is equal to the ratio of the number of turns of the winding they connect to. For example, connecting the load between the middle and bottom of the autotransformer will reduce the voltage by 50%. Depending on the application, that portion of the winding used solely in the higher-voltage (lower current) portion may be wound with wire of a smaller gauge, though the entire winding is directly connected.
Autotransformers are often used to step up or down between voltages in the 110-117-120 volt range and voltages in the 220-230-240 volt range, e.g., to output either 110 or 120V (with taps) from 230V input, allowing equipment from a 100 or 120V region to be used in a 230V region.
Operation
An autotransformer has a single
winding with two end terminals, and one or more terminals at
intermediate tap points. The primary voltage is applied across two of
the terminals, and the secondary voltage taken from two terminals,
almost always having one terminal in common with the primary voltage.
The primary and secondary circuits therefore have a number of windings
turns in common.Since the volts-per-turn is the same in both windings, each develops a
voltage in proportion to its number of turns. In an autotransformer part
of the current flows directly from the input to the output, and only
part is transferred inductively, allowing a smaller, lighter, cheaper
core to be used as well as requiring only a single winding
As in a two-winding transformer, the ratio of secondary to primary voltages is equal to the ratio of the number of turns of the winding they connect to. For example, connecting the load between the middle and bottom of the autotransformer will reduce the voltage by 50%. Depending on the application, that portion of the winding used solely in the higher-voltage (lower current) portion may be wound with wire of a smaller gauge, though the entire winding is directly connected.
Sunday, February 12, 2012
Sunday, January 29, 2012
Saturday, January 28, 2012
ASUS Readies Latest Motherboards for Upcoming Six-core CPUs
Full Range of AMD-based Motherboards are Ready to Support Six-Core for Next-generation Personal Computing
ASUS
today announced a full range of motherboards that are ready to support
the upcoming six-core AMD® Phenom™ II X6 processors to herald a new era
in ultra-powerful personal computing. Early Praises from Media Organizations World-wide
Ready for AMD six-core processors, the ASUS M4 Series motherboards deliver maximum performance on a mainstream platform. Other than the readiness of supporting six-core processors, Joe Hsieh, General Manager of ASUS Motherboard Business said, “the ASUS M4 Series also gives users of every level the best performance and value with its Core Unlocker feature. This has received notable recognition from many of the world’s top media organizations for delivering a phenomenal boost in performance.” M4 Series motherboards with exclusive Core Unlocker technology have also garnered global media accolades for being the best motherboard for AMD processors.Simple BIOS Upgrade For Six-core Activation
ASUS’ M4 Series motherboard is ready for the AMD® Phenom™ II X6 processors. To enable 6-core CPU and achieve maximum performance, users simply need to update the BIOS of their existing M4 Series.Five Overclocked GeForce GTX 560 Cards, Rounded-Up
We were foiled in our quest to find the best vendor-provided
GPU cooler for Nvidia's GeForce GTX 560. But out of the ashes sprung a
round-up of cards armed with those very same solutions. Which of these
five GF114-based boards is right for you?
This story was conceptualized as a means to compare graphics card coolers from different vendors. Because no two GPUs have the exact same overclocking headroom, we wanted to take one GeForce GTX 560 and drop solutions from Asus, ECS, Galaxy, MSI, and Zotac onto that bare board. With thermal, acoustic, and performance data, we would have been able to give you a definitive answer as to whose heat sink and fan combination does the best job of pulling heat away from Nvidia's GPU. Surely, this would have been great information to have when overclocking.
Unfortunately, that plan was foiled by a number of variables that we simply couldn’t overcome to our satisfaction. For example, the cooler designers employ a surprisingly diverse range of fan power cable plugs, which aren't interoperable with any one card's connector. Moreover, fan temperature profiles vary from one card's firmware to another's, affecting our thermal and acoustic results.
With five GeForce GTX 560 cards in-hand, though, we still had the makings of a respectable round-up. So, we abandoned the idea of isolating cooler/fan effectiveness and forged ahead to bring you a comprehensive look at five examples of Nvidia's roughly-$200 contender.
As you can see, there’s a wide range of specifications applied to these cards, none of which match Nvidia’s reference 810 MHz core and 1002 MHz frequencies. The Galaxy model comes closest with its 830/1002 MHz clocks, but Zotac's AMP! edition goes all the way to 950/1100 MHz.
There’s a lot more distinguishing one board from the others than operating clock rates, though, as all of the coolers are unique as well. There's only one that matches the reference design. Some cards also include value-adds like games, and the Galaxy MDT supports as many as four display outputs and triple-monitor surround gaming. Of course, we also have to gauge how far our samples can be overclocked.
This story was conceptualized as a means to compare graphics card coolers from different vendors. Because no two GPUs have the exact same overclocking headroom, we wanted to take one GeForce GTX 560 and drop solutions from Asus, ECS, Galaxy, MSI, and Zotac onto that bare board. With thermal, acoustic, and performance data, we would have been able to give you a definitive answer as to whose heat sink and fan combination does the best job of pulling heat away from Nvidia's GPU. Surely, this would have been great information to have when overclocking.
Unfortunately, that plan was foiled by a number of variables that we simply couldn’t overcome to our satisfaction. For example, the cooler designers employ a surprisingly diverse range of fan power cable plugs, which aren't interoperable with any one card's connector. Moreover, fan temperature profiles vary from one card's firmware to another's, affecting our thermal and acoustic results.
With five GeForce GTX 560 cards in-hand, though, we still had the makings of a respectable round-up. So, we abandoned the idea of isolating cooler/fan effectiveness and forged ahead to bring you a comprehensive look at five examples of Nvidia's roughly-$200 contender.
| Asus GTX 560 DirectCU II TOP | ECS Black GTX 560 | Galaxy MDT4 GeForce GTX 560 | MSI N560GTX Twin Frozr II OC | Zotac GeForce GTX 560 AMP! | |
|---|---|---|---|---|---|
| Graphics Clock | 925 MHz | 870 MHz | 830 MHz | 870 MHz | 950 MHz |
| Shader Clock | 1850 MHz | 1740 MHz | 1660 MHz | 1640 MHz | 1900 MHz |
| Memory Clock | 1050 MHz | 1000 MHz | 1002 MHz | 1020 MHz | 1100 MHz |
| GDDR5 Memory | 1 GB | 1 GB | 1 GB | 1 GB | 1 GB |
| Cooler | DirectCU II | Reference | Custom | Twin Frozr II | Custom |
| Size | 10.25" x 5" | 9.5" x 5" | 8.75" x 5" | 10" x 5" | 9.5" x 5" |
| Connectors | 2 x DL-DVI, 1 x mini-HDMI | 2 x DL-DVI, 1 x mini-HDMI | 4 x DVI, 1 x mini-HDMI | 2 x DL-DVI, 1 x mini-HDMI | 2 x DL-DVI, 1 x mini-HDMI |
| Form Factor | Dual-slot | Dual-slot | Dual-slot | Dual-slot | Dual-slot |
| GPU Voltage | 0.912 V Idle 1.012 V Load | 0.950 V Idle 0.987 V Load | 0.912 V Idle 0.987 V Load | 0.912 V Idle 0.987 V Load | 0.912 V Idle 1.15 V Load |
| GPU Voltage Adjustment | Asus Smartdoctor | Not supported (MSI Afterburner) | Galaxy Xtreme Tuner HD | MSI Afterburner | Not supported (Stock 1.15 V) |
| Special Features And Software | N/A | N/A | Quad-Display Support | Includes game: Lara Croft and the Guardian of Light | Includes game: Assassin's Creed: Brotherhood |
| Warranty | 3-Year parts & labor | 2-Year labor 3-Year parts | 2-Year labor 3-Year parts (if registered in 30 days) | 3-Year parts & labor | 2-Year Standard, Limited Lifetime Extended (if registered in 30 days) |
| Newegg Price | $219.99 | $192.99 | $229.99 | $199.99 | $219.99 |
As you can see, there’s a wide range of specifications applied to these cards, none of which match Nvidia’s reference 810 MHz core and 1002 MHz frequencies. The Galaxy model comes closest with its 830/1002 MHz clocks, but Zotac's AMP! edition goes all the way to 950/1100 MHz.
There’s a lot more distinguishing one board from the others than operating clock rates, though, as all of the coolers are unique as well. There's only one that matches the reference design. Some cards also include value-adds like games, and the Galaxy MDT supports as many as four display outputs and triple-monitor surround gaming. Of course, we also have to gauge how far our samples can be overclocked.
Friday, January 27, 2012
Thursday, January 26, 2012
Tuesday, January 24, 2012
Wednesday, January 11, 2012
Active and Passive Devices
What are Active Devices?
An active device is any type of circuit component with the ability to electrically control electron flow (electricity controlling electricity). In order for a circuit to be properly called electronic, it must contain at least one active device. Active devices include, but are not limited to, vacuum tubes, transistors, silicon-controlled rectifiers (SCRs), and TRIACs.
All active devices control the flow of electrons through them. Some active devices allow a voltage to control this current while other active devices allow another current to do the job. Devices utilizing a static voltage as the controlling signal are, not surprisingly, called voltage-controlled devices. Devices working on the principle of one current controlling another current are known as current-controlled devices. For the record, vacuum tubes are voltage-controlled devices while transistors are made as either voltage-controlled or current controlled types. The first type of transistor successfully demonstrated was a current-controlled device.
What are Passive Devices?
Components incapable of controlling current by means of another electrical signal are called passive devices. Resistors, capacitors, inductors, transformers, and even diodes are all considered passive devices.
Passive devices are the resistors, capacitors, and inductors required to build electronic hardware. They always have a gain less than one, thus they can not oscillate or amplify a signal. A combination of passive components can multiply a signal by values less than one, they can shift the phase of a signal, they can reject a signal because it is not made up of the correct frequencies, they can control complex circuits, but they can not multiply by more than one because they lack gain.
An active device is any type of circuit component with the ability to electrically control electron flow (electricity controlling electricity). In order for a circuit to be properly called electronic, it must contain at least one active device. Active devices include, but are not limited to, vacuum tubes, transistors, silicon-controlled rectifiers (SCRs), and TRIACs.
All active devices control the flow of electrons through them. Some active devices allow a voltage to control this current while other active devices allow another current to do the job. Devices utilizing a static voltage as the controlling signal are, not surprisingly, called voltage-controlled devices. Devices working on the principle of one current controlling another current are known as current-controlled devices. For the record, vacuum tubes are voltage-controlled devices while transistors are made as either voltage-controlled or current controlled types. The first type of transistor successfully demonstrated was a current-controlled device.
What are Passive Devices?
Components incapable of controlling current by means of another electrical signal are called passive devices. Resistors, capacitors, inductors, transformers, and even diodes are all considered passive devices.
Passive devices are the resistors, capacitors, and inductors required to build electronic hardware. They always have a gain less than one, thus they can not oscillate or amplify a signal. A combination of passive components can multiply a signal by values less than one, they can shift the phase of a signal, they can reject a signal because it is not made up of the correct frequencies, they can control complex circuits, but they can not multiply by more than one because they lack gain.
Friday, January 6, 2012
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