# VCCS

Discussion in 'Electronic Basics' started by Joshua Michael Huffman, May 13, 2005.

1. ### Joshua Michael HuffmanGuest

Hi, i have a voltage controlled current source that is being short
circuited. What happens if the controlling voltage is not zero?

R1 a R2 c
o--/\/\/\---o----/\/\/\----o-------o------o
| | | |
+ \ / \ \ |
V1 / R3,Vab /gVab\ / R4 |
- \ \ / \ |
| \ / | |
| | | |
o-----------o--------------o-------o------o
b d

Here is a rough picture... I'm trying to find the h parameters of this
circuit, in particular "h21" where (c,d) is shorted out... In case you
want to know....

R1 = 100 ohm
R2 = 10e6 ohm
R3 = 2.5e3 ohm
R4 = 100e3 ohm
g = 40 mA/V

Here are the ans. straight from my book.

H11 = 2.6e3 ohm
H12 == 2.5e-4
H21 = 100
H22 = 2e-5 conductance

I can get the first two but i'm still working on H21 any help would be
appreciated. I general, i dont know how the vcvs behaves when it shorted.
Any help would be appreciated.

Josh

3. ### Andrew HolmeGuest

If you short-circuit a current source, the current flows through the short,
and the voltage across it is zero.  