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plzz help...Referee electronics

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mehdi999

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I look for the possible equations for this circuit
 

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My guess is a two player Jeopardy Game style response circuit. First response locks out other.

Ken
 
yes ..KMoffett

and i'm looking for the equations of this circuit ???
can anyone help or give me an idea plzzz
 
With both switches open, both transistors are in cut-off (not conducting), the lamps are out, and resistor end of the switches are at +E voltage through the left lamp and R1, in series, and through the right lamp and R2 in series. If the right switch is the first one closed, the current supplied from +E, through the left lamp and R2 supplies base current to turn on T2. T2's collector-emitter voltage drops to about 0.2V and supplies a current path through the right lamp, lighting it. Because the base current for T1 would be provided through R1 from T2's collector, which is now only 0.2V, T1 cannot be turned on...it's locked out. E has to be disconnected to reset the game.

ken
 
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I think he is looking for the values of R and E, but he needs to post what kind of bulbs he is using
 
i have 2 transistor t1=t2=2N2222A , Ic=150 mA,Fhe=100 , E= 5 volt Vce=30 volt 2 lamp with 450 mA

i'm looking for R1 , R2 , R3 , R4
 
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Have you learned Kirchhoff's Voltage Law (KVL) and Mesh current method?

Is there a particular law your teacher wants you to use to solve it?
 
no there is no particular law i want just to have the equations of this circuit
after having it i will calculete my R1234 ALONE
 
Look at the datasheet values for high collector currents: https://www.fairchildsemi.com/ds/PN/PN2222A.pdf
At 500mA the hfe is not 100. For guarantied collector-emitter saturation I usually use hfe/10. Base current would be Ilamp/(hfe/10). R1 and R2 would equal the supply voltage minus the base-emitter voltage, divided by the base current. ~ (E-Vbe)/((Ilamp/(hfe/10))
R3 and R4 are there just to hold the bases at ground when the switches are open...so...anything a lot higher than R1 or R2..... I'd use R1=R3x100 up to R3x10000

Post your answers!

Ken
 
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