uciradiuzivaj | elektrotehnika

ELEKTROTEHNIKA

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LED as Voltage Indicator

Most of the electronic devices have an indicator, which shows the device is energized.
We can connect a resistor and an LED in parallel to the device’s supply terminals, also we can place a diode for protection against polarity reversal. The input voltage source turns on the LED and device simultaneously. The LED remains on until the energy reaches the device.

Zener and Schottky Diodes

A Zener diode is a special type of diode designed to reliably allow current to flow “backward” (i.e., from cathode to anode) when a certain set reverse voltage, known as the Zener voltage, is reached. Zener diodes are used for voltage regulation purposes. Normal diodes are composed of a PN junction. Schottky diodes have a semiconductor-metal junction, instead. A metal-semiconductor junction has metal in contact with the semiconductor material. Forward voltage drop of Schottky diodes is smaller in comparison with normal PN junction diodes. Schottky diodes have a high speed switching as well.

Breadboard

A breadboard is used for building temporary circuits. It is useful to designers because it allows components to be removed and replaced easily or person who wants to build a circuit to demonstrate its action and then to reuse the components in another circuit. Breadboard holes are connected to each other according to the pattern shown above on the right figure. The long horizontal rails with + and – labels are usually connected to the energy source, i.e. battery.
Let's make the below circuit on a breadboard:

Placing the ICs on the Breadboard

Different ICs have different packages. Some of the most famous packages are dual-in-line package (DIP), surface-mount device (SMD), small-outline IC (SOIC), small-outline package (SOP), quad-flat package (QFP), quad-flat no-leads (QFN), small-outline transistor (SOT), and ball-grid array (BGA).

Only ICs with DIP package can be connected to a breadboard.

IP addressing

IP addressing, or Internet Protocol addressing, is a method used to assign unique numerical addresses to devices connected to a computer network. These addresses, called IP addresses, serve as identification for devices and enable them to communicate with each other over the network.

· IPv4 addresses are 32 bits in length, with each bit being either a 0 or a 1. They are represented in decimal format with four groups of eight bits each. For example, an IPv4 address may look like 192.168.1.196.
· IPv6 addresses are 128 bits in length and are represented in hexadecimal format with eight groups of four hexadecimal digits each. Leading zeros within each group can be omitted, and consecutive groups of zeros can be represented with double colons (::). For example, an IPv6 address may look like 2001:0db8:85a3:0000:0000:8a2e:0370:7334.

In the IPv4 IP address space, there are five classes: A, B, C, D and E. Each class has a specific range of IP addresses (and ultimately dictates the number of devices we can have on our network). Primarily, class A, B, and C are used by the majority of devices on the Internet. Class D and class E are for special uses.

Within each network class, there are designated IP addresses that are reserved specifically for private/internal use only. These IP addresses cannot be used on Internet-facing devices as that are non-routable. For example, web servers and FTP servers must use non-private IP addresses. However, within our own home or business network, private IP addresses are assigned to our devices (such as workstations, printers, and file servers).

Class A addresses always begin with a "0" in the highest order bits.
Class B addresses always begin with a "10" in the highest order bits.
Class C addresses always begin with a "110" in the highest order bits.
Class D addresses always begin with a "1110" in the highest order bits.
Class E addresses always begin with a "11110" in the highest order bits.

Class A addresses range from 1-126; 0 is reserved and represents all IP addresses; 127 is reserved address and is used for testing, like a loopback on an interface.
Class B addresses range from 128-191.
Class C addresses range from 192-223.
Class D addresses range from 224-239.
Class E addresses range from 240-254; 255 is reserved address and is used for broadcasting purposes.