Casecode Configuration
- Thread starter rainman
- Start date
okay i will post anther one ... thanks for ur concern
The Electrician
- Joined Oct 9, 2007
- 2,970
You haven't said just how exact your solution must be, but an approximate solution is fairly easy. First, assume the base current of each transistor has a negligible effect on the bias network (beta is 200, so this is reasonable).
Treat the three resistor network of Rb1, Rb2 and Rb3 as an unloaded voltage divider and calculate the voltage at the base of each transistor. If the transistors are silicon, then the emitter voltages are about .7 volts lower than the corresponding base voltage.
Knowing the voltage at the emitter of Q1, you can calculate the emitter current of Q1. Since the betas are high, the collector currents and emitter currents are almost equal (more exactly, the collector is the emitter current minus the base current, but remember that beta is 200).
In reality, the collector currents are a little smaller than the emitter currents, and the base currents do slightly load the bias network, so an iteration or two will improve the accuracy of the solution.
Once you have the currents, you should be able to calculate the gain. If you have trouble with that, come back here, and show what you are able to calculate.
Treat the three resistor network of Rb1, Rb2 and Rb3 as an unloaded voltage divider and calculate the voltage at the base of each transistor. If the transistors are silicon, then the emitter voltages are about .7 volts lower than the corresponding base voltage.
Knowing the voltage at the emitter of Q1, you can calculate the emitter current of Q1. Since the betas are high, the collector currents and emitter currents are almost equal (more exactly, the collector is the emitter current minus the base current, but remember that beta is 200).
In reality, the collector currents are a little smaller than the emitter currents, and the base currents do slightly load the bias network, so an iteration or two will improve the accuracy of the solution.
Once you have the currents, you should be able to calculate the gain. If you have trouble with that, come back here, and show what you are able to calculate.
You May Also Like
-
Intel Clocks ‘World’s Fastest Desktop Processor’ at 6.2 GHz Frequency
by Jake Hertz
-
Exclusive Interview—Flux Partners With Ultra Librarian to Tap Its Ecosystem
by Jeff Child
-
Generative AI Meets Its Computing Match in Nvidia’s New GPU
by Jake Hertz
-
Kioxia First to Release UFS 4.0 Embedded Flash Memory for Automotive
by Jake Hertz
