Answer / pappu

Magnetic Field. https://en.wikipedia.org/wiki/Hall_effect
If Magnetic Field is a known quantity then Hall Effect can be used to measure proximity and velocity also. With 4 hall devices in a wheatstone bridge you can even measure direction of magnetic field. This is how you can see directions (North) on your smart phone. Next time just Google for Hall Effect.

how to switch on electrical appliances through mobile call not sms please refer me connections detail or even link will do ?

1 Answers  

---

the two inputs to and gate are 4V and 5V.if threshold voltage is 0.5V.then what is output of and gate?if input voltage is reduced to 0.52V each,then what will be output?

2 Answers   Intel,

---

why u join indian army

52 Answers   Indian Army, SSB, UES,

---

if once can say that after 3 year at which position do you see yourself

2 Answers   Wipro,

---

Filtering can be done with ?

0 Answers   Verifone,

---

---

What is a multiplexer?

13 Answers  

---

WHEN DO WE USE CAPACITOR AND INDUCTOR AS STORING DEVICE?

2 Answers  

---

why should you consider youself fit to be hired by jspl

0 Answers   manappuram,

---

Why emitter is always forward biased?

0 Answers  

---

wath is this mining of hlr

0 Answers   Nokia,

---

How does a cell phone works?

0 Answers   CTS,

---

what are the advantage of pmmc?

2 Answers  

---