Wiring And Schematic

RF power amplifier circuit of this work is based on the transistor 2SC1970 and 2N4427. The set output power of 88-108 MHz FM RF Amplifier With 2SC1970 is about 1.3W and the input driver is 30-50mW. RF driver amplifier circuit uses a 2N4427 and its power amplifier using a transistor 2SC1970.

At the time of the amplifier circuit tuning FM 88-108 MHz RF Amplifier With 2SC1970 should use the power meter / watt meter or SWR or RF field can also use the meter. RF amplifier circuit can work from the frequency of 88-108 MHz.

Circuit of 88-108 MHz FM RF Amplifier With RF 2SC1970 can radiate far enough. At the time of tuning you should use a 50 Ohm dummy load. For the input signal should be installed to regulate the VR level so as not to over-modulation (30-50mW).

This design is based on the 18 Watt Audio Amplifier, and was developed mainly to satisfy the requests of correspondents unable to locate the TLE2141C chip. It uses the widespread NE5532 Dual IC but, obviously, its power output will be comprised in the 9.5 - 11.5W range, as the supply rails cannot exceed ±18V.

As amplifiers of this kind are frequently used to drive small loudspeaker cabinets, the bass frequency range is rather sacrificed. Therefore a bass-boost control was inserted in the feedback loop of the amplifier, in order to overcome this problem without quality losses. The bass lift curve can reach a maximum of +16.4dB @ 50Hz. In any case, even when the bass control is rotated fully counterclockwise, the amplifier frequency response shows a gentle raising curve: +0.8dB @ 400Hz, +4.7dB @ 100Hz and +6dB @ 50Hz (referred to 1KHz).

Numbers in parentheses show IC1 right channel pin connections.

Set the volume control to the minimum and R3 to its minimum resistance.

The afterward diagram is 16W Bridge audio amplifier circuit. The ambit congenital based 2 pieces of ability IC LM383 in arch connection, so this amplifier is an arch amplifier.

Simple and low cost. The optimal accumulation voltage is about 50V, but this amp assignment from 30 to 60V. The acute ascribe voltage is about 0.8 – 1V.
As you can see, in this architecture the apparatus accept a big tolerance, so you can body it about of the components, which you acquisition at home. The and transistors can be any NPN blazon ability transistor, but do not use Darlington types… The achievement ability is about 60W.

- capacitor C1 regulates the low frequencies (bass), as the capacitance grows, the low frequncies are accepting louder.

- capacitor C2 regulates the college frequencies (treble), as the capacitance grows, the college frequencies are accepting quiter.

- this is a chic B amplifier, this means, that a accepted charge breeze through the end transistors, alike if there is no arresting on the input. This accepted can be adapted with the 500Ω trimmer resistor. As this accepted incrases, the complete of the amplifier gets better, but the end transistors are added heating. But if this accepted decrases, the transistors are not heating so much, but the complete gets worse…

Stereo amplifier is very simple, consisting of 5 active components including the power supply it. Series Stereo Amplifier With Tube was prepared with 5 units trioda tube consisting of 1 unit tubes 5Y3 GT vacuum rectifier, 2 tube tube trioda 6SF5 GT high-mu tube 6k6 and 2 units which form the power beam amplifiers. Power consumption for the circuit with a tube stereo amplifier is not more than 45 Watt. Current consumption for the circuit with a tube stereo amplifier is around 3A. A complete range of stereo amplifiers with this tube can be seen from the following series of images.

Stereo Amplifier With Tube

Sign Component Stereo Amplifier With Tube

R1, R10, R13 2.2M

R2 470K 1/2W

1 Meg 1/2W R3

R4 220K 1/2W

R5 330 Ohm 2W

R6 220K 1/2W

R7 2.2Meg 1/2W

R8 1Meg 1/2W

R9 720 Ohm 20W

R11 33K 1/2W

R12 22K 1/2W

C1, C9 400V 0.005uF

C2 0.05uF 600V

C3 20uF 25V

C4 0.01uF 400V

C5 200uuF 400V

C6, C7 15uF 450V

C8 15uF 400V

T1 117V Primary, Secondary 350VCT, 2 × 6.3V

T2 7600 Ohm Primary, Secondary 4 or 8 Ohm

SW1 SPST Switch

SP1, SP2 12 "4 / 8 ohm

C8 in the series stereo tube amplifier with the above serves to reduce radio frequency interference and to optimize the work of a wild series of ampifier stereo with these tubes.

Author: D. Prabakaran - Copyright: Electronics For You Mag

Ethics of integrated amplifier class A is IC1 - NE5532 to develop indicate input through the C1 to proliferation 15-fold. The signal output from the pin 1, signal hemisphere assured through C2 to access Q1-BD139 and Q3-2N3055. is powered by dear ton, amplifiers and gesture the intensification of the no characteristic of C3 through the amplifier with the Q2-BD140 and Q4-MJ2955.

This is the beloved ton, too. after that the output signal from the helpful side of the pin E of the Q3 and the off-putting border of the pin unfashionable of the E concerning Q4 through R10 and R11, to prevent brief circuits and therefore output to the speakers. This bidding power up to 5 watts. The D1-D4 acts while a rectifier in the DC bias in favor of Q1 and Q2. And VR1 is adjusted to a constant current bias is next to masterpiece. The Q1-Q4 will be situated attached sheet cooled, Q3 and Q4, especially the thermal plate have got to be sizeable. for the reason that the circuit has high spot energy loss

                                                     Figure 1 - Low Power VersionHigh Power Version
The same PCB is used, but has an extra pair of MOSFETs. Since the devices are running in parallel, source resistors are used to force current sharing. Although these may be replaced by wire links, I do not recommend this. This version may be operated at a maximum supply voltage of +/-70V, and will give up to 180W RMS into 8 ohms, and 250W into 4 ohms. Short term (peak) power is around 240W into 8 ohms and 380W into 4 ohms. These figures are very much dependent on your power supply regulation, determined by the VA rating of the transformer, size of filter caps, etc.




                                                     Figure 2 - High Power Version

Although not shown, the transistors and MOSFETs are the same in this version as for the low power variant. The additional capacitors (C11 and C12) shown are to balance the gate capacitance. The P-Channel MOSFETs have significantly higher gate capacitance than their N-Channel counterparts, and the caps ensure that the two sides of the amp are roughly equal. Without these caps, the amp will almost always be unstable.

As noted above, the PCB is the same for both versions, but for Fig. 2 it is fully populated with 2 pairs of power MOSFETs. The high power version may also be used at lower supply voltages, with a slight increase in power, but considerably lower operating temperatures even at maximum output, and potentially greater reliability.

With both versions, the constructors page gives additional information, and the schematics there include an enhanced Zobel network at the output for greater stability even with the most difficult load. This is provided for on the PCB, and allows the amp to remain stable under almost any conditions.

The entire circuit has been optimised for minimum current in the Class-A driver, while still providing sufficient drive to ensure full power capability up to 25kHz. The slew rate is double that required for full power at 20kHz, at 15V/us, and while it is quite easy to increase it further, this amp already outperforms a great many other amps in this respect, and faster operation is neither required nor desirable.

    Note - There are actually two caps marked C5, and two marked C6. This is what is on the PCB overlay, and naturally was not found until it was too late. Since these caps cannot be mixed up, it will not cause a problem.

In both versions of the amp, R7 and R8 are selected to provide 5mA current through the voltage amplifier stage. You will need to change the value to use a different supply voltage ...

    R7 = R8 = Vs / 10 (k)   (Where Vs is one supply voltage only)

For example, to set the correct current for ±42V supplies ...

    R7 = R8 = 42 / 10 = 4.2k (use the next lower standard value - 3.9k)

Construction
The suggested power supply is completely conventional. Although a small amount of additional power can be obtained by using an auxiliary supply (to boost the rail voltage for the MOSFET drive stage), this is at the expense of greater complexity and more things to go wrong. The transformer for the supply should be matched to the expected power you wish to obtain from the amp. The following table shows the recommended transformer voltage and VA rating for a single channel - either use two transformers or a single unit with twice the VA rating shown for stereo.

    AC Volts    DC Volts    VA    Power (8Ω)
    20-0-20    +/-28V        100        40
    25-0-25    +/-35V        100        50
    30-0-30    +/-42           160        80
    40-0-40    +/-56V         200       150    (Recommended Supply Voltage)
    50-0-50    +/-70V         300       240

Note that all powers shown are "short term" or peak - continuous power will always be less as the supply collapses under load. Peak power levels are usually achieved (or approached) with most music because its transients are generally between 6dB and 10dB greater than the average power output. Transformer VA ratings shown are a guide only - larger or smaller units may be used, with a marginal increase or reduction of peak power. Always use at least the size shown for subwoofer use! Values in bold are preferred, and will give enough power for most systems along with optimum reliability and low operating temperature.

                                              Figure 3 - Power Supply Circuit Diagram

Figure 3 shows the power supply circuit diagram for a ±56V supply, and there is nothing new about it. As I always recommend, the bridge rectifier should be a 400V/35A chassis mount type, and should be properly chassis mounted using heatsink compound.

Filter capacitors must be rated to at least the nominal supply voltage, and preferably higher. If possible, use 105°C rated caps, and join the earthed terminals very solidly to form the star earthing point.

    Note - The fuse should be selected according to the size of the power transformer. For any toroidal transformer over 300VA, a soft start circuit is highly recommended. Use the transformer manufacturers suggested fuse - if this information is not available, ask the supplier - not me!

The DC supply must be taken from the capacitor terminals - never from the bridge rectifier. Using several small capacitors will give better performance than a single large one, and is usually cheaper as well. For example, the performance of 10 x 1,000uF capacitors is a great deal better (in all respects) than a single 10,000uF cap, at between 50% to 70% of the cost of the large unit. This lunch is not free, but it is heavily discounted

Here is a circuit Power Amplifier with output power of more than 600 Watt speakers with impedance of 4 Ohm. Power Amplifier circuit with high power uses n-channel MOSFETs 6 in the output stage alone is giving about 400Watt power. And to make more than 600Watt need to use 12 N-Channel MOSFETs. One of the construction sequence to produce more output power of 900W using 12 IRFP460 MOSFET. Here is a Power Amplifier Circuit Diagram, and the Power Supply is suited for this amplifier. I also include a PCB Layout Design for the power amplifier and its power supply, you can see below.

This Circuit Use a IC BA515 for operation it. This is very simple Amplifier schematic , with only add 8 component , such as resistor and capacitor. Minimum voltage require 3 Volt , this also low voltage amplifier . And maximum voltage require 9 volt. Power output under 10 Watt with impedance 4 Ohm. This circuit is very suitable for small speakers.