4 Transistor 500mW FM Transmitter Circuit Diagram

4 Transistor 500mW FM Transmitter Circuit Diagram

As shown, the audio ascribe is a microphone, which uses 2 x 2N3904 as the microphone audio preamplifier. The audio/mic ascribe akin is adjustable by agency of a 5k preset / potentiometer.

The ambit uses a Colpitts oscillator for abundance generation, which is chargeless active and operates at the axiological abundance i.e. no circuitous abundance multiplication or control. The abundance affability basic of the ambit consists of 2 5pF (picoFarad) capacitors and a distinct 10uH (micro-Henry) inductor. These apparatus can be adapted if a change in abundance is appropriate - conceivably alike replaced with capricious capacitors (if youre up to the challenge).

An achievement RF amplifier takes the abundance produced by the Colpitts oscillator and amplifier to about about the 500mW (0.5 Watt) ambit - so this is the almost achievement ability of this FM transmitter. You are brash that back this transmitter operates at the axiological frequency, and because there is no achievement filter, there is acceptable to be some abundance alluvion and harmonics/spurious emissions.

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2N3904 Transistor datasheet Diagram Circuit Emitter Follower Circuit Diagram

The schematic shown below diagrams the emitter follower circuit using 2N3904, an NPN silicon bipolar junction transistor. In the circuit provided, input signal is applied to the base of the transistor, but the output is taken from the emitter.
Instead of using 2N3904 transistors, this emitter follower circuit uses such parameters: 40V collector to emitter voltage (Vce), 6V emitter to base voltage (Veb), 200mA collector current (Ic), 300mW power dissipation (Pmax), 300Mhz frequency where internal capacitances cause gain to be reduced to unity (fT), 10pF internal emitter-base capacitance (Ceb), and 3pF internal base-collector capacitance (Cbc). 

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LM317T based Voltage Regulator with Pass Transistor circuit

Here is the circuit diagram for LM 317 T voltage regulator with pass transistor .

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Cry Baby wah wah pedal Schematic Diagram transistor 2n3904

Cry Baby wah wah pedal Schematic Diagram used transistor 2n3904

Cry Baby wah wah pedal Schematic Diagram transistor 2n3904

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LED FLASHER WITH ONE TRANSISTOR

LED FLASHER WITH ONE TRANSISTOR

This is a novel flasher circuit using a single driver transistor that takes its flash-rate from a flashing LED. The flasher in the photo is 3mm. An ordinary LED will not work.

The flash rate cannot be altered by the brightness of the high-bright white LED can be adjusted by altering the 1k resistor across the 100u electrolytic to 4k7 or 10k.

The 1k resistor discharges the 100u so that when the transistor turns on, the charging current into the 100u illuminates the white LED.

If a 10k discharge resistor is used, the 100u is not fully discharged and the LED does not flash as bright.

All the parts in the photo are in the same places as in the circuit diagram to make it easy to see how the parts are connected.

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