Power amplifier electronic circuits-tube audio rf amplifiers

Electronic Amplifier Circuits-Power amplifier, audio amplifier designs and circuits

April 27th, 2010

Cable TV Amplifier Using Transistors

Circuit Description

The circuit diagram of Cable TV amplifier has been published here. This cable TV amplifier circuit consists of two transistors Q1 and Q2 both 2SC1324 as its core part. Type number of these transistors is optional; any medium power NPN RF transistors can be used instead of it. Among these transistors Q1 is meant for amplification and gives a maximum gain of around 20 dB. Transistor Q2 functions as emitter follower. This emitter follower circuit is meant for increasing current gain.

12V DC supply is used for powering this circuit.  It is most applicable for cable TV systems that use coaxial cables of 75 ohms. This particular amplifier has less performance than other high quality cable TV amplifiers available in market since it is a simple elementary circuit.

Circuit Diagram

Cable TV Amplifier Using Transistors

Cable TV Amplifier Using Transistors

Notes

  • Use a Vero board to assemble components for this particular circuit.
  • This amplifier works fine up to 150 MHz in cable TV systems that use 75 ohm coaxial cables.


April 27th, 2010

IC TDA 2003 Amplifier

Circuit Description

The circuit diagram of 10W amplifier using TDA 2003 has been published here. This simple amplifier circuit is based on a central IC TDA 2003 developed by SGS Thomson. This IC has some advanced features like short circuit protection, thermal overload protection, low harmonic and cross over distortions etc. This circuit is designed after the datasheet of IC TDA 2003 provided by the vendor.

In this circuit, gain of the amplifier is determined by the resistors R2 (220 ohm) and R3 (2.2 ohm). The upper cut off frequency is determined by capacitor C3 (39 nF) and resistor R1 (39 ohm). The stability of the amplifier at high frequencies is accomplished by capacitor C6 () and resistor R4 (1 ohm). Input DC decoupling is done by capacitor C7 (10 uF) and output is coupled to the speaker by C5 (100 uF).

18V DC supply is used in this circuit to give power. Adequate heat sinks must be provided for TDA 2003. This amplifier delivers maximum power of 10W to a 4 ohm load at 18V supply. This IC has an advantage of working in a range of supply voltage from 12 V to 18V. In order to get maximum performance of this circuit on PCB, input and output grounds must be properly decoupled.

Circuit Diagram

IC TDA 2003 Amplifier

IC TDA 2003 Amplifier

Notes

  • Use a good quality PCB to assemble this circuit.
  • IC TDA 2003 is suitable for car audio systems.
  • Adequate heat sink should be provided for TDA 2003.
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