🔍 Key Concepts

• Simple-oscillator emergency transmitters and how they generate RF energy • Where the keying circuit is usually placed in relation to the power supply and RF stages • Safety and practicality when switching high-voltage versus low-level circuits

💭 Think About

• Think about what happens if you interrupt current in the primary of a high-voltage transformer. Is that usually considered safe and practical for a simple emergency unit? • Consider whether you normally key RF by switching the high-voltage supply, or by switching a lower-voltage/low-power part of the circuit. • If you placed the key in series with the final output to the antenna, how would that affect the tuning and loading of the transmitter?

✅ Before You Answer

• Which option avoids routinely switching dangerous high voltage directly with the key? • Which arrangement would cause the least disturbance to the tuning and loading of the RF output circuit? • Verify which location is most common in simple CW (Morse) transmitters for keying: power-supply primary, keying the oscillator stage, or breaking the antenna lead.