Visual modulation indicator

Posted on Nov 4, 2012

Indicator lamp brightness varies in step with modulated RF signal. Adjust R2 with transmitter on (modulated) until the lamp flashes in step with modulation

Visual modulation indicator
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Cl = 5 pf, C2 = 100 pF, Dl = 1N60 or 1N34 (Germanium), R3 - 10 K pot, II = 6-8 V, 30-60 mA incandescent bulb, Q1 = 2N3393 (for increased sensitivity use 2N3392 or other high-gain transistor).

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