PIN Diodes and Control Circuits — Lesson 2

This lesson covers the fundamentals of PIN diodes and their application in control circuits. It explains the structure of a PIN diode, its behavior under reverse and forward biased conditions, and its equivalent circuit representation. The lesson further delves into the use of PIN diodes as switches, discussing single-pole single-throw (SPST) and single-pole double-throw (SPDT) switches. It also explains how the impedance of the device can be controlled by changing the bias of the device, enabling a switching action. The lesson concludes with a discussion on the use of PIN diodes in designing phase shifters.

Video Highlights

00:28 - Introduction to PIN diodes and its equivalent circuits
04:26 - SPST series switch
09:42 - SPST shunt switch
14:50 - Introduction to single-pole double-throw type switches
18:08 - Discussion on how PIN diodes can be used in designing phase shifters

Key Takeaways

- PIN diodes contain an intrinsic or lightly doped layer between P and N layers, reducing junction capacitance and making forward conductivity more linear.
- Under reverse bias conditions, the diode impedance is high, while under forward bias conditions, the diode is in a low impedance state.
- PIN diodes can be used as switches, with the impedance controlled by changing the bias of the device.
- Single-pole single-throw (SPST) and single-pole double-throw (SPDT) switches can be created using PIN diodes.
- PIN diodes can also be used in designing phase shifters, creating a differential phase shift in the signal.