Electronics-Lab.com Community

# prateeksikka

Members

736

1. ## +- power supplies

just for a beginner : for any circui to function with reliablity except for special autotransformers, +/-5V is equivalent to 0 and 10V supply. potential difference requires no reference but a potential does. thats it. ;D
2. ## Help Needed Calculating Resistance

from this topic i used bicolor LED once in my lifetime. i guess u also remember the same.can u guess? it was in electronic stethoscope---the fuzzzzzzzzy project......
3. ## Resistance wattage in series

hi audioguru! what will be the case according to u when the resistors are in parallels? then i guess current through them being unequal and voltages being equal we would have P=P1*P2/(P1+P2) as the net power rating where P1 and P2 are the individual power ratings. am i right?
4. ## Help Needed Calculating Resistance

hi audioguru! do u really have 1.8V LEDs? i mean how do u have a voltage above 0.7V in forward bias condition?
5. ## Resistance wattage in series

hi audioguru! say we have 2 resistors with wattage P1 and P2 and connected in series. the current through them is same i=V/(R1+R2) net resistance=R1+R2 in such a case it can be written as V*V/P=V*V/P1+V*V/P2. thus 1/P=1/P1+1/P2 thus reciprocals added give reciprocal of net power.what do u say?
6. ## Help Needed Calculating Resistance

well i make it a golden rule: current in an LED should not exceed 14mA and normally 5k in series with a single LED is enough........ u can calculate it easily for any circuit...
7. ## Resistance wattage in series

i guess what bloki said is not correct. wattage of the resistors is added only when they are connected in parallels and not in series. whats the view of others?
8. ## filter

hi walid! i see no prblm in calling it as allow instead of emphasis. yes some active filters do provide some gain to the signals as is the case with butterworth filters of high pass or low pass kinds. filters are an integral part of signal processing circuits where we want some frequencies to be passed with high and some with low attenuation. they also find appliocations in detectors of all kinds.all your FM ,AM receivers ,TVs computers would not have been possible without the use of filters......
9. ## Momentary Switch from Piezoelectric Transducer

hi ardeo check out this link: http://www.imagesco.com/catalog/sensors/switch-info.html
10. ## Ultrasonic cleaner

hi dude! as far as the circuit is concerned , i cant directly help u and most of the companies manufacturing it have patents for it. Bad news! ;D
11. ## NPN vs PNP choice

hi all! Whenever we go for a design, say for an amplifier should i chose a pnp or an npn transistor (as electrons have higher mobility), negative voltages are a problem always, isnt that so?

i guess u wish to have a variable frequency of the crystal to be controlled through a controller. am i right? ADC with variable frequency clock?
13. ## What's a snubber capacitor, and what's it used for?

Thank god! all s well that ends well
14. ## What's a snubber capacitor, and what's it used for?

Actually we generally use a series combination of a resistor and a capacitor which is known collectively as a snubber circuit. It protects the thyristor.I guess cap alone will not even work!
15. ## electornics and communication

u can start up with a diode in preliminary stage and use it as an AM envelope detector. go ahead good luck.No schematic at all!

hi duratia! most of the ADCs have external clocks.... tell me the number of the ADC anyway.
17. ## What's a snubber capacitor, and what's it used for?

hi friend! snubber capacitors are used to protect expensive devices like thyristors against surge voltages which may appear across them in form of sudden spikes. capacitor acts as short fo high frquency and current does not flow through the device initially but increases slowly as the cap is charged.... thats it
18. ## Antenna and TV standard

hi audioguru! do u mean that the cable wire carries frequency multiplexed audio and video signals? i mean audio at one and video at other frequency but sharing same channel(cable wire)

connection to ADC depends on Pin Diagram of the ADC u are to use. Make sure that it is well synchronized with i/p data frequency and sampling rate of ADC. Dallas Chips are most famous as ADCs...
20. ## Increased voltage!

Even i felt that ! But there could be one thing Power is same and voltage is increased at cost or reduced current. Is that possible just like a transformer.
21. ## what is unipolar pam

hi audioguru! i guess we hardly use PAM for digital modulation i guess PTM has more advantages. and know one thing,i just came to know that there is a fallacy in the name itself of PCM(it is not a modulation scheme)! cheers!
22. ## Increased voltage!

thats why the people follow such practices. anyhow is there any way to get an increased voltage ? my very vague guess goes in the direction of negative swing which earth might be providing -130 to 130V makes it 260V right? anyone in support? ur comments ante?
23. ## Increased voltage!

hi ante! people of indian villages normally follow this practice when voltage is low (130 V)but most appliances run here on 230V. I have single phase 2 wire in my house. there also it works.
24. ## Antenna and TV standard

hi audioguru! do the video(AM) and audio signals(FM) in a TV come from the same antenna. i guess they differ in frequency by a large amount. how do they travel after antenna in same single wire?
25. ## Increased voltage!

come on friends! views on my qustion of increased voltage when groung dipped in moist mud or clay? I guess some where the voltage is swinging in negative direction. no?otherwise it cant happen. it is simply strange buddies! anyone who would like to experiment?
×