Analog Electronics AGH Class Exercises

Diode

Exercise1 Diode, operation point, static and dynamic operation.

Ud (V)	0.58	0.6	0.7	0.75
Id(A)	0.6	1	3	4

1. Draw the characteristic of a diode as given in the table above. Find its dynamic resistivity and the threshold tension

2. Give the equivalent circuit for forward biased diode.

3. Draw the load line and find graphically bias point (operation Q point ) of the diode for the circuit as given in fig 1 . E=4V, R = 1Ω.

Fig 1

1. Maximum power dissipated on this diode e is P_max=3W. Find graphically U_dmax and Id_max

2. Illustrate Ud(t), Id(t), U_R(t) for the situation as shown in figure 2 (alternative tension e is put in series with E), E_m<<E

3. Give the equivalent scheme for static operation and determine the bias Q point found in question 3

4. Give the equivalent scheme for small signals and determine the dynamic output u_d(t) ;i_d(t) i u_R(t) ;E_m<<E (illustrated in 5)

Fig2

7. Diode is taken here as a LED type. Operation point is fixed as Ud=3V, id=10 mA. Find R if E=12V ( car battery case)

Exercise 2 Pic detector

1. Illustrate the signal of tensions and currents in a pic detector shown in fig 3. 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

fig 3

1. Illustrate the signal of tensions and currents in a pic detector shown in fig 5. Consider this diode as a perfect one i.e U_F=0, and that E_m>>U_F Start from the case when R=∞

Rys.5

Remove next resistivity R and replace it by the pic detector from Fig.3. Illustrate the tensions on two capacitors. Conclusions.

Exercise 3 Limitting, clipping circuits

Explain the operation of the circuits shown below. Draw s = f (e ) for

E1=5 V, e=10 sin(2πft), f=100 Hz.

For circuit # 1 determine the Thevenin’s equivalent circuit for two cases: e>E1 and e<E1

(circuits 2 and 3 => individual work at home)

Appendix

Charge and discharge of a capacity in an elementary RC circuit