Electronic devices and circuit theory

1. Clampers
Mateen chaudhary

2. clampers

3. clampers
• A network that shifts a waveform to a
different level
• Does not change the appearance of the
applied signal
• Time constant
t=RC

4. Operation of clampers

5. clampers
• Positive clampers
– Shifts its input waveform in a positive direction
– lies above a dc reference voltage
• Negative clampers
– shifts its input waveform in a negative direction
– lies below a dc reference voltage

6. Positive clampers

7. Positive clampers
In ideal case

8. clampers
• Clamping is not perfect since diode drops
0.7V.
Negative peak

9. Working of positive clamper
• Negative half cycle
– Conduct and act as short
circuit and Output v=0
– Capacitor is charged to peak
value and behave like battery
• Positive half cycle
– Does not conduct and act as open circuit
– Output voltage
vo=vm+vm

10. Positive clamper

11. Negative clamper

12. Working of negative clampers
• Positive half cycle
– diode conducts and acts like
a short circuit
– Capacitor is charged to peak
value and behave like battery
Output v=0
• Negative half cycle
– diode is open and output can be found by
applying KVL

13. Negative clamping
• vm-vm-vo =0
• Vo=-2vm

14. Clamping networks

15. Application of clampers
• Test equipment
• Radar systems
• Sonar systems
• Electronic counter measure systems
• Used in TV receivers as a DC restorer