Page 93 - Build Your Own Transistor Radios a Hobbyists Guide to High-Performance and Low-Powered Radio Circuits

RF

Transformer

FIGURE 6-2 An RF tra,nsformer in the commercially made two-transistor
radio.

The figure shows the Windsor radio's RF transformer with primary and secondary
windings indicated. Unfortunately, though, such an RF transformer is not readily
available today.
One-Transistor TRF Reflex Radio

Some of the goals for a single-transistor reflex radio are to work at 3 volts or less,
drain about 250 IJA using a crystal earphone, and provide workable performance at
1.5 volts. And yet another goal is to design this radio without the type of RF

transformer seen in Figure 6-2.
As Figure 6-1 shows, inductive and/or transformer loads are used in both transistor
stages. Inductive and transformer loads to the collectors of the transistors allow for
the collectors actually to swing a higher voltage than the battery supply_ Those who