Posted on Mar 24, 2013

Because power MOSFETs offer high power gain at both audio and radio frequencies, they are useful in many areas of radio-circuit design. For rf applications, a MOSFET`s large safe operating area, V0 s vs ! 0, protects it against damage from reflected rf energy. As a modulator, a MOSFET`s transfer linearity aids fidelity. In the suppressed-carrier modulator, an rf signal is applied to the primary of transformer Tl, whose secondaries provide equal-amplitude, opposite-phase rf drive signals to output FETs Ql and Q2.

Click here to download the full size of the above Circuit.

Output V. is zero when no audio-frequency signals are present, because the opposite-phase rf signals from Ql and Q2 cancel. When audio-frequency signals appear at nodes A and B, you obtain a modulated rf output (I";,). Source resistors Rl8 and Rl9 improve the de stability and low-frequency gain. A phase inverter, based on the dual op amp IClA and IClB, generates the out-of-phase, equal-amplitude, audio-frequency modulation signals.

Leave Comment

characters left:

New Circuits



Popular Circuits

de amst wiskar: robot line folower
Simple Metal Detector
sequential timer circuit diagram using 22
Weller WLC100 Electronic Soldering Station Circuit Q4012LPH
Creating an HID Ballast with Constant Lamp Power Control
Capacitor Meter Circuit
Vegetable greenhouse temperature detection control circuit
Discrete components sound and light control stairs delay switch circuit 9
XTR110 circuit diagram using an external PNP transistor
Trickle charger circuit schematics