Qualification > Sciences
Physics Help HERE ONLY !!
SGVaibhav:
http://upload.wikimedia.org/wikipedia/commons/2/23/Thermally_Agitated_Molecule.gif
Shogun:
--- Quote from: saadmannan on May 28, 2009, 11:26:16 pm ---Can somebody plz explain me
1) Thermistor
2)Transistor
3) Diode Rectification
4) LDR
--- End quote ---
hi,thermistor is a type of a resistor, except tht it works depending on the temperature. if the temperature was at cold the resistance increases, and as resistance increases the current is acroos it reduces.
so in short the lower the temperature the higher the resistance.
now, the transistor, u see, is an elctronic switch, an automatic switch u see, it has 3 sets of wire joind as a circuit, the 3 wires are base,collector and emitter.it allows somthing (eg: a lamp) to work depending on 2 condition which are: 1) there must be a current on the base wire(ie. there must be a base current)
2)the potential difference(P.D) betwwen base and emitter path must be atleast 0.6volts.
if these 2 conditions are not there then the lamp is automatically switched off.
then therez the diode, its positive side must be connected to the positive side of the battery(the same was the ammeter is connected) then it will allow current to flow throgh (i.e no resistance). what is its job? it changes an AC current to DC.Now, if the positve side of this device is connected to the negative side of the battery the resistance would be high and would not conduct electricity(i.e it wont allow current to pass).
then finally the light dependant resistor(LDR). this thing is like the thermistor...except it depends on light.if light falls on it the resistance decreases thus allowing current to pass, in short, if light touches it the resistance decreases.
hope u understand, any difficulties, or problems, or confusion u have plz do ask me.
cactus_360:
can anyone explain potential divider briefly.................
leebux101:
potential divider is like a variable resistor...u can vary the voltage tht is being provided to one device and the other as well according to the voltage tht is need for the devices...or just vary the voltage and resistance and compare current and stuff like tht...
i am not sure abt this...u shud ask someone else just in case...
good luck!
Shogun:
--- Quote from: cactus_360 on May 29, 2009, 03:22:41 pm ---can anyone explain potential divider briefly.................
--- End quote ---
yup wat bakhtawar said was correct, it devides the voltage accross the circuit to parts or devices.
for eg: this much voltage1 for device 1 and this voltage2 is for device2,what does the potential devider do is tht it can take some voltag1 to voltage2 so now device2 has more voltage. its job is to devide the voltage.
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