Analog Electronics AGH Class Exercises

Supply devices

Exercise 2 Supply rectifiers and pic detector

1. Illustrate the signal of tensions and currents in a full wave rectifier shown in fig 4. Consider this diode as a perfect one i.e. U_F=0, Rd<<R and that E_m>>U_F Start from the case when C=0

Propose the transmission rate of this transformer in order to obtain U_R≈+15V , for e_rms=220V

rys 4

How does change U_R(t) when R decrease?

1. Give the circuit of the full wave rectifier , using the Gretz bridge . What are the benefits and defects of this solution?

Exercise 4 Zener diode

Zener diode of Uz= 45 V is used to stabilize the variations of the signal e which changes within the limits 40-60 V R_L=1.8 k

1 Give Rs which provides that for e=40 V, I_s=20 mA,

2. Give the relation s=f( e) for 0< e <80 V. What is the minimal value of e which assures the correct stabilization? Take Rd=0 Ω

3.. Find I_d for e=60V, What happens with I_d when e increases? Take Rd=0 Ω

4. Propose the equivalent Thevenin’s scheme of the stabilizer and characterize it using following form:

Δs.=KΔe-R Δi_L

Determine the equivalent resistivity R and stabilization ratio K (advice : take as e= E +Δe look for the small signal output only , use Thevenin principle ) , take Rd=50 Ω