FREQUENCY
Frequency ka matlab hota hai “kitni baar koi cheez kisi samay ke dauraan hoti hai”. Ye aam taur par waveforms, sound, ya signals ke context mein use hota hai.
Explanation:
👉 Frequency ek measurement hai jo batata hai ki 1 second mein koi event kitni baar repeat hota hai.
Iski unit hoti hai Hertz (Hz).
1 Hz = 1 baar per second
Examples se samajhte hain:
Fan ka speed: Agar fan ek second mein 3 baar ghoomta hai, to uski frequency hai 3 Hz.
Music/Sound: Jab hum kehte hain koi awaaz high frequency pe hai, iska matlab uski vibration zyada fast ho rahi hai — jaise ek teekhi (sharp) awaaz.
Simple Summary:
Frequency = Kitni baar koi kaam 1 second mein hota hai
💡 Jaise humari dil ki dhadkan ki frequency bhi hoti hai — 72 times per minute approx!
WHAT IS FREQUENCY? (Frequency kya hoti hai?)
🔸 Alternating current (AC) ki frequency ka matlab hota hai ki ek AC sine wave ek second mein kitni baar cycle complete karti hai.
🔸 Frequency yeh batati hai ki current ek second mein kitni baar direction change karta hai. Isse Hertz (Hz) mein measure kiya jaata hai.
🔸 1 Hertz (Hz) ka matlab hota hai 1 cycle per second.
📌 Kuch Important Terms:
Hertz (Hz) = 1 Hertz ka matlab hota hai 1 cycle har second mein.
Cycle = Ek poori wave jo alternating current ya voltage ko show karti hai.
Alternation = Ek aadha cycle (ya to positive ya negative part).
Period = Ek poori cycle complete hone mein jo time lagta hai, use period kehte hain.
🔁 Simple Tarike Se:
Basic level pe, frequency ka matlab hota hai koi cheez kitni baar repeat hoti hai.
Electrical current ke case mein, frequency ka matlab hota hai ki sine wave ek second mein kitni baar positive se negative jaake wapas aati hai.
👉 Jitni zyada cycles har second mein hoti hain, frequency utni hi zyada hoti hai.
🔌 Kuch Common Frequencies ke Example:
Power line frequency:
Generally hoti hai 50 Hz ya 60 Hz, jo hamare ghar ke bijli (electricity) ke liye use hoti hai.Variable-frequency drives (VFD):
Inmein 1 se 20 kilohertz (kHz) tak ki carrier frequency hoti hai. Yeh motors ka speed control karne ke liye use hoti hai.Audio frequency range:
15 Hz se 20 kHz tak — yeh wo range hai jo insaan sun sakta hai.Radio frequency:
30 kHz se 300 kHz tak — yeh radio signals ke liye use hoti hai.Low frequency (LF):
300 kHz se 3 megahertz (MHz) tak hoti hai.Medium frequency (MF):
3 MHz se 30 MHz tak hoti hai.High frequency (HF):
30 MHz se 300 MHz tak hoti hai.
(WiFi ki frequency kya hoti hai?)
📶 Tumhara wireless router radio frequency ka use karta hai taaki internet signal WiFi-connected devices (jaise smartphones, laptops, tablets, etc.) tak bhej sake.
2.4 GHz vs 5 GHz WiFi ka Difference:
Dono 2.4 GHz aur 5 GHz ek type ki WiFi frequency bands hain.
Main difference hota hai speed aur range ke beech.
🔍 Thoda detail mein samjhte hain:
Feature | 2.4 GHz WiFi | 5 GHz WiFi |
|---|---|---|
Range | Zyada door tak signal jaata hai | Kam distance cover karta hai |
Speed | Thodi slow hoti hai | Zyada fast speed deta hai |
Interference | Zyada devices is band pe kaam karte hain, isliye interference ho sakta hai (microwaves, Bluetooth, etc.) | Kam interference, kyunki kam devices use karte hain |
Wall Penetration | Achha signal milta hai diwaar ke paar bhi | Diwarein signal ko rok sakti hain |
📡 Radio Frequency Spectrum Bands Table
| Band Name | Frequency Range | Use Case (Upyog) |
|---|---|---|
| Very Low Frequency (VLF) | 3 – 30 kHz | Submarine communication, long-distance signaling |
| Low Frequency (LF) | 30 – 300 kHz | Navigation systems, AM longwave radio |
| Medium Frequency (MF) | 300 kHz – 3 MHz | AM Radio |
| High Frequency (HF) | 3 – 30 MHz | Shortwave radio, aviation |
| Very High Frequency (VHF) | 30 – 300 MHz | FM radio, TV broadcasts |
| Ultra High Frequency (UHF) | 300 MHz – 3 GHz | TV, mobile phones, WiFi (2.4 GHz, 5 GHz) |
| Super High Frequency (SHF) | 3 – 30 GHz | Radar, satellite communication, 5G |
| Extremely High Frequency (EHF) | 30 – 300 GHz | Advanced radar, high-frequency data links |
FREQUENCY
(2.4 GHz vs 5 GHz: Kaunsi frequency choose karni chahiye?)
2.4 GHz connection zyada door tak signal bhejta hai, lekin speed thodi kam hoti hai.
5 GHz frequency zyada fast speed deti hai, lekin uska range chhota hota hai.
➡️ Tumhe 2.4 GHz ya 5 GHz ka selection is baat pe depend karega ki tum WiFi ka use kaha aur kaise karte ho.
Bohot saare electronic devices jaise ki microwave, baby monitor, security camera, aur garage door opener 2.4 GHz frequency ka use karte hain.
Agar tumhare ghar mein aise devices zyada hain, ya tum apartment ya flat mein rehte ho, toh 2.4 GHz band zyada congested ho sakta hai.
Is wajah se WiFi ki speed aur signal quality kharaab ho sakti hai.
| Band name | abbr. | ITU band | Frequency | Wavelength | ** Bands Allocated to Amateurs |
| Extremely low frequency | ELF | 1 | 3 – 30 Hz | 10,000-100,000 km | none |
| Super low frequency | SLF | 2 | 30 – 300 Hz | 1,000 – 10,000 km | none |
| Ultra low frequency | ULF | 3 | 300 Hz – 3 kHz | 100 – 1000 km | none |
| Very low frequency | VLF | 4 | 3 – 30 kHz | 10 – 100 km | none |
| Low frequency Longwave (LW)* | LF | 5 | 30 – 300 kHz | 1 – 10 km | 2200 m |
| Medium frequency Medium-wave (MW)* | MF | 6 | 300 – 3000 kHz | 100 – 1000 m | 630, 160 m |
| High frequency * Short-wave (SW) | HF | 7 | 3 – 30 MHz | 10 – 100 m | 80, 60, 40, 30, 20, 17, 15, 12, 10 m |
| Very high frequency | VHF | 8 | 30 – 300 MHz | 1 – 10 m | 6, 4, 2, 1.25 m |
| Ultra high frequency | UHF | 9 | 300 – 3000 MHz | 10 – 100 cm | 70, 23, 13 cm |
| Super high frequency | SHF | 10 | 3 – 30 GHz | 1 – 10 cm | 5, 3, 1.2 cm |
| Extremely high frequency | EHF | 11 | 30 – 300 GHz | 1 – 10 mm | 6, 4, 1 mm |
