Power amplifier electronic circuits-tube audio rf amplifiers

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

June 9th, 2010

Switching Regulator Circuit

Circuit Description

The circuit diagram of 3A switching regulator has been published here. The central part of this circuit is the IC LM 317. This voltage regulator can deliver a maximum output current of 3A. The input voltage range of this circuit is between 8 and 35V DC. The output voltage of the circuit can be adjusted between 1.8 to 32V DC. The output voltage is adjusted by using the potentiometer R4 (5K). One of the main advantages of switching regulators over liner regulators is its power efficiency.

Switching regulator operates by taking energy from the input voltage source and then transferring it to the output with the help of a solid state switch and a control circuitry. There is no wastage of energy in switching voltage regulators since the switching element is either fully open or closed at any moment. The efficiency of switching voltage regulators is around 85%. The rate of energy transfer from input to output is controlled by the control circuit by controlling the duty cycle of the solid state switch.

Circuit Diagram

Switching Regulator Circuit

Switching Regulator Circuit

Notes

  • Use a good quality PCB to assemble this circuit.
  • The electronic circuit given here is a simple and low cost switching regulator.
  • Adequate heat sinks should be provided for IC1 and Q1.
  • Capacitor C1 must be a solid tantalum capacitor.

May 13th, 2010

6 Volt Regulator Circuit

Circuit Description

The elementary circuit diagram of 6V voltage regulator has been given here. The main part of this circuit is the voltage regulator IC 7806. . This IC 7806 is a three-terminal positive voltage regulator. This IC is suitable for a wide range of applications in voltage regulator circuits. This IC has some advanced features such as internal current limiting, thermal shut down and safe operating area protection. These features make this IC indestructible. At normal conditions with heat sink, this IC can deliver an output current of 1A.

230V AC input is taken through step-down transformer and is rectified using a bridge rectifier circuit. Following this a capacitor filter network is used for filtering the rectifier output. The filtered signal is given to the IC 7806.

Circuit Diagram

6 Volt Regulator Circuit

6 Volt Regulator Circuit

Pin Diagram of 7806

7806 Pin Diagram

7806 Pin Diagram

Notes

  • Use a good quality PCB to assemble this particular circuit.
  • The IC 7806 is available in the TO-220/D-PAK package.
  • Adequate heat sink should be provided for the IC 7806 if this circuit draws more than 400mA current.
  • Use four 1N 4007 diodes if 2A Bridge is not available for the rectifier circuit.

May 7th, 2010

25 Volt Adjustable Voltage Regulator Circuit

Circuit Description

The circuit diagram of 25V Adjustable Regulator has been given here. This circuit is based on LM 117 IC which is the central part of this circuit. The LM117 IC is an adjustable 3-terminal positive voltage regulator. This voltage regulator is able to provide in excess of 0.5A over a 1.2V to 37V output range. The added advantages of this circuit is that the ease of handling and the use of only two external resistors for setting the output voltage.

In this circuit, voltage adjustment is done by using the resistors R1 and R2. This power supply for this circuit is able to deliver a maximum of 0.5A current. By adjusting the potentiometer R2, required voltage can be obtained. To reduce min output voltage from 1.2 volt to 0V, connect two IN4007 diodes in series to the output.

Circuit Diagram

25 Volt Adjustable Voltage Regulator Circuit

25 Volt Adjustable Voltage Regulator Circuit

LM 117 Pin Diagram

lm117 pin diagram

lm117 pin diagram

Notes

  • For getting a 1.2A output current replace LM117 with LM317.
  • This circuit is easy to assemble and provides great results.
  • Adequate heat sink should be provided for IC LM 117.
  • To get a 1.2A output current replace LM117 with a LM317.
  • You can use as less as 5V DC as input voltage. Here a minimum 28V, 2A DC input is needed for the IC as shown in figure.
  • If exact value components are not available then try the nearest ones.
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