A simple crystal receiver for the beginner
Tuesday, 8 March 2011
Ramsey Electronics Model QRP-40 CW Transmitter
Schematic diagram for the Ramsey Electronics Model QRP-40 CW Transmitter. This easy-
to-build CW transmitter provides about one watt of output RF power in the 40-meter
band. Ramsey Electronics Inc.
Code practice oscillator
Schematic diagram for code practice oscillator circuit using the Signetics NE555 IC
Timer.
Cigar·lighter polarity Tester
Before you plug your equipment into the cigar lighter of your new (or an unknown) car, it's a good idea to test the lighter polarity. Fig shows a simple means of doing this. The circuit tests for a center positive condition at the lighter; if the lighter is powered, and + 12 volts is connected to its center contact, DSllights. Carry this gadget with your "pluggable" 12-V gear; it could save your transceiver from a quick demise.
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