O'Reilly logo

Build Your Own Transistor Radios by Ronald Quan

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Chapter 9Low-Power Superheterodyne Radios

Chapter 8 presented superheterodyne radios of moderate current drain (e.g., >10 mA) that powered loudspeakers. This chapter will explore superheterodyne receivers with extremely low current draw that allow years of continuous playing on a single battery. What we will find out is that the superheterodyne circuit topology shown in Chapter 8 will not apply for low-power design, and instead, a modified circuit topology is required.

Design Goals for Low Power

The design goals are as follows:

1. Current drain of less than 150 μA with a crystal earphone

2. Operational supply voltage of 1.2 volts

3. Sensitivity and selectivity performance at least equal to that of the four-transistor design in Chapter 8

As with ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required