Is it easy to learn PHP?
Is it easy to learn PHP?
How do you define a constant?
A constant is an identifier (name) for a simple value. The value cannot be changed during the script. A valid constant name starts with a letter or underscore (no $ sign before the constant name). Note: Unlike variables, constants are automatically global across the entire script.
What is the difference between HTML and PHP?
HTML is a language used to describe to a browser how to display text and other objects in a browser window. It is not a programming language. HTML works on a client computer (the system on which the page is being viewed). PHP is a scripting language, and can be used to create web pages written in HTML.
What is the universal logic gate?
A universal gate is a gate which can implement any Boolean function without need to use any other gate type. The NAND and NOR gates are universal gates. In practice, this is advantageous since NAND and NOR gates are economical and easier to fabricate and are the basic gates used in all IC digital logic families.
What is the propagation delay of a logic gate?
In computer networks, propagation delay is the amount of time it takes for the head of the signal to travel from the sender to the receiver. It can be computed as the ratio between the link length and the propagation speed over the specific medium.
What is the processing delay?
Processing delay is a key component in network delay. During processing of a packet, routers may check for bit-level errors in the packet that occurred during transmission as well as determining where the packet’s next destination is.
What is fan in of a logic gate?
Fan-in is the number of inputs a logic gate can handle. For instance the fan-in for the AND gate shown in the figure is 3. Physical logic gates with a large fan-in tend to be slower than those with a small fan-in. This is because the complexity of the input circuitry increases the input capacitance of the device.
What is Noise Margin in digital circuits?
In electrical engineering, noise margin is the amount by which a signal exceeds the minimum amount for proper operation. It is commonly used in at least two contexts: In a digital circuit, the noise margin is the amount by which the signal exceeds the threshold for a proper ‘0’ or ‘1’.
Can CMOS drive TTL?
In the LOW state, a TTL output can drive CMOS directly. However, the guaranteed TTL HIGH output level of 2.4 volts is not a valid input level for CMOS. If the TTL output drives only CMOS inputs, then essentially no current is drawn and the HIGH output may be 3.5 V or higher.
Is CMOS or TTL faster?
CMOS compared to TTL: CMOS circuits do not draw as much power as TTL circuits while at rest. However, CMOS power consumption increases faster with higher clock speeds than TTL does.
What is meant by TTL logic?
Transistor-transistor logic (TTL) is a digital logic design in which bipolar transistor s act on direct-current pulses. Many TTL logic gate s are typically fabricated onto a single integrated circuit (IC). A TTL device employs transistor s with multiple emitters in gates having more than one input.
What is RTL logic?
Resistor–transistor logic (RTL) is a class of digital circuits built using resistors as the input network and bipolar junction transistors (BJTs) as switching devices.
What is ECL logic?
In electronics, emitter-coupled logic (ECL) is a high-speed integrated circuit bipolar transistor logic family. ECL uses an overdriven BJT differential amplifier with single-ended input and limited emitter current to avoid the saturated (fully on) region of operation and its slow turn-off behavior.
What is TTL and ECL?
Emitter Coupled Logic (ECL), also referred to as Current Mode Logic families, is a digital technology with extremely high-speed. Transistors are not allowed to go into deep saturation thus, eliminating storage delays like in TTL logic families. Transistors are driven either in cut off or in active region.
What is a logic family?
A logic family of monolithic digital integrated circuit devices is a group of electronic logic gates constructed using one of several different designs, usually with compatible logic levels and power supply characteristics within a family. Some such logic families use static techniques to minimize design complexity.
How hard is it to learn PHP?