Wien Bridge

The Bridge In the figure is presented a Wien Bridge. When its two arms are at equilibrium ($R1*R3=R2*R4$) the voltage on the Wien bridge diagonal cancels. You apply to this bridge a voltage $V(t)=100*\cos(100 t)$ V and to you are using an oscilloscope with $R(in)=1M\Omega$. a) You determine the voltage between a) and b) directly.

Head and Tails Toss

How does the following circuit works as a heads and tails toss? AnswerThe circuit is symmetric. However due to tolerances of the electrical components when first placed under tension one transistor will be blocked, and the other will be open. The basis of the transistors are polarised (when first placed under voltage) by the LED,