Wide band high frequency amplifier

This is Wide band high frequency amplifier circuit, a Wide frequency band between 75-150 MHz, Using transistors, a PNP amplifier. To enhance the signal strength. Before the receiver of the phone. Or FM radio or amateur radio.

If high-frequency signals, in particular, its VHF. The booster circuit is one, serves to amplify the signal strength only.

Operation of the circuit

High-frequency range VHF, inductive antenna, to the emitter pin of the transistor Q1. so circuit held, in conjunction with the bass, a nice low output impedance. You can use a special access code 50 ohms, the antenna on the circuit at all.

The Signal at the Q1 will be expanded to increase. And sent to a tuner or receiver to the receiver.

Wide band high frequency amplifier

Figure 1 The wideband high frequency amplifier circuit.

The L1 coil wire enamel No. 24 SWG, thousands of rounds of 10, inside diameter 3 mm. And the coil L2 wire number. Thousands of 13 turns, diameter 5 mm. Stent both as a non-core, or an air core.

The power supply is +5 V, this circuit while current is 2.5 mA. If the components to use. Should be based on the antenna. And design of high frequency printed circuit boards as well.

How to assemble circuits

The assembling circuit onto the universal PCB board as Figure 2 May have problems, the interference inserted come in, If assembly circuit to actually use. Should have a basic antenna and PCB design in high frequency reasonable.

The components list

Resistors size ¼ W +5%
R1, R2: 18K
R3: 1.5K
R4: 220 ohm
Capacitors
C1, C3: 0.0056uF 50V
C2: 56pF 50V
C4: 5.6pF 50V
Semiconductor
Q1: BF324___PNP Transistors
Others
L1: is 10 turns of 24 SWG enamel coated magnet wire wound with an inside diameter of about 3mm. no core.
L2: is 13 turns of 24 SWG enamel coated magnet wire wound with an inside diameter of about 5 mm. no core.
The Universal PCB board

components-layout-of-wide-band-high-frequency-amplifier
Figure 2 the component layouts of this circuit

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This Post Has 3 Comments

  1. The BF324 transistor has a transition frequency of 450MHz, which is not much higher than common transistors like the 2N3906 (pnp) or 2N3904 (npn). This is one reason why the common-base configuration is used here. A npn transistor like the BF199 might be a better bet, but the polarity of the supply would need to be reversed. As both supply lines are at ground potential as far as signal voltages are concerned, the output could still be referenced to the negative rail.

    1. Thank you very much for your good advice. Your experience is very valuable. Hope to return to visit our website again.

  2. Could you put L3 as opposed to L2 as output instead of output

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