forum gods come 2gether & answer newb transistor questio

[ibanezts808]

Okay,  I'm still getting the hang of sll of this stuff.  When I bias a transistor, am I basically making it so the voltage going into the collector is between the switch off and max collector voltage?  Also, I was making a mystery pedal it is a battery, transistor, resistor, and the jacks.
here are the specs:  

2n3904 npn transistor
   Ic Max(A) - 0.2
   V(BR)CBO Min (V) - 60
   Hfe Min - 100
   Hfe Max - 300
   fT Min (MHZ) - 250
47k resistor
9v battery

the battery runs to resistor, resistor runs to collector, guitar goes to base, emitter goes to output.  This is a portion of the elektra distortion pedal found at http://www.geocities.com/CollegePark/Library/1355/beginners.htm it is referred by generalguitargadgets, so I believe it is a working schematic.  I just ripped the first part to see if I could get some amplification, and well.  I'm not. It drops the signal, I tried a smaller resistor and the signal was stronger, and I tried no resistor and the signal was stronger, but not stronger then when I went direct into an amp.  Thank you.

[petemoore]

Okay,  I'm still getting the hang of sll of this stuff.  When I bias a transistor, am I basically making it so the voltage going into the collector is between the switch off and max collector voltage?  Also, I was making a mystery pedal it is a battery, transistor, resistor, and the jacks.
here are the specs:  

2n3904 npn transistor >>>Should work
   Ic Max(A) - 0.2
   V(BR)CBO Min (V) - 60
   Hfe Min - 100
   Hfe Max - 300
   fT Min (MHZ) - 250
47k resistor
9v battery

the battery runs to resistor, resistor runs to collector, guitar goes to base, emitter goes to output.  This is a portion of the elektra distortion pedal found at http://www.geocities.com/CollegePark/Library/1355/beginners.htm it is referred by generalguitargadgets, so I believe it is a working schematic.  I just ripped the first part to see if I could get some amplification, and well.  I'm not. It drops the signal, I tried a smaller resistor and the signal was stronger, and I tried no resistor and the signal was stronger, but not stronger then when I went direct into an amp.  Thank you.

input cap to base and  2m2 that goes to collector and 47k which goes to V+. a 680*Ohm tied from emitter to ground. Output from 2M2, collector and 47k...100k to ground after all that. Has to work.
 Transistor pinout.
 Verify that EBC are like from bottom to top, and transistor is facing toward output...no check the data sheet and graft the tranny in there the right way if it's not.
 Take transistor pin voltages [E,B,C] from ground and post 'em.

[niftydog]

instead of ripping off parts of circuits you don't understand and hoping they'll work, why don't you go and find a web site that has some basics about class A amplifiers and build a simple one that is tried and tested.

You'll get nowhere fast doing it this way.

Even better, continue building the beginner project that Aron has so helpfully set up and learn to analyse it once it's working.

[b_rogers]

try reading this:


http://www.tpub.com/neets/book7/25c.htm


hope this helps


Brent