Wi-Fi standards
2.4GHz 802.11g
IEEE 802.11g was one of the main Wi-Fi standards to follow on from 802.11a and 802. 11b.IEEE 802.11g has an advantageous because it supports a high data speeds using 2.4 GHz which was only attainable using 802.11a within the 5GHz ISM band.
The 802.11g uses OFDM technology initiated with 802.11a. just Like 802.11a, it supports up to a maximum theoretical rate of 54 Mbps. But like 802.11b, it operates in the crowded 2.4 GHz. 802.11g is reversed compatible with 802.11b gadgets: an 802.11b device can connect to an 802.11g access point (but at 802.11b speeds). With 802.11g, consumers enjoyed a significant advance in Wi-Fi speeds and coverage. Consumers non-wired routers were getting better at the same time , with better coverage and higher power than earlier generations.
2.4 GHz 802.11n (Wi-fi 4)
Is a wireless-networking standard which uses more than one antennas to increase data rates, 802.11n uses multiple input / multiple output (MIMO) technology and a wider radio frequency channel. It also provides a mechanism called frame aggregation to reduce time between transmissions. it can transmit a series of frames without having to release the channel and regain authority for each frame. raw data throughput is expected to reach as much as 600 Mbps — that’s more than 10 times the throughput of 802.11g.
2.4 GHz 802.11ac (wi-fi 5)
802.11ac supercharges Wi-Fi, with speeds ranging from 433 Mbps all the way up to several Gigabits per second. To achieve this kind of performance, 802.11ac works exclusively in the 5 GHz band, supports up to eight spatial streams (compared with 802.11n’s four streams), doubles the channel width up to 80 MHz, and uses a technology called beamforming. With beamforming, the antennae basically transmit the radio signals so they’re directed at a specific device.
Another significant advancement with 802.11ac is multi-user (MU-MIMO). While MIMO directs multiple streams to a single client, MU-MIMO can direct the spatial streams to multiple clients simultaneously. While MU-MIMO doesn’t increase the speed to any single client, it can increase the overall data throughput of the entire network.
As you can see Wi-Fi performance continues to evolve, with potential speeds and performance nearing wired speeds.
4GHz 802.11b 2.
During transmission of data 802.11b usually use the CSMA/CA technique that was defined in the original 802.11 base standard and retained for 802.11b. 802.11b cards are normally specified to operate at a basic rate of 11 Mbps
802.11b is a success story of the IEEE 802.11 standards. Initially it was used in computer gadget as smartphones were Wi-Fi connectivity within mobile phones were not commonplace. Nevertheless IEEE 802.11b was used in many applications and enabled future versions of the standard to build on its success.
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Effective resistance
Resistance in series (A) =1Rt=1R1 + 1R2
= 110+14
40/17
Resistance in series (B) =1Rt=1R1 + 1R2
= 18+11
=8/9
Effective resistance (Rt)
Resistance in parallel=R1+R2+R3
=40/17 +8/9 + 3
= 6.746
But E=IR
Therefore 12=I (6.746)
I= 1.770A