Mj2955+7805 5V 5A power supply for digital circuit.

This is circuit dc regulator power supply 5V at current 5A, I used it for my digital production. The mian part electronics is IC 7805 and Mj2955 tansistor.
You must use the the 9VAC 5A transformer.

Circuit power supply 5V 5A by 7805+Mj2955

PCB Power supply 5V 5A by 7805+Mj2955
Source: 79 Electron circuit

MJ2955 for IC 78xx Boosting Regulator Current circuit and explanation

Source :: http://www.zen22142.zen.co.uk/Circuits/Power/boosti.htm
IC 78xx series of voltage regulators are available with different current outputs, you can boost
the available current output with this circuit. A power transistor is used to supply extra current to the load
the regulator, maintaining a constant voltage. Currents up to 650mA will flow through the regulator, above
this value and the power transistor will start to conduct, supplying the extra current to the load. This should
be on an adequate heat sink as it is likely to get rather hot. Suppose you use a 12v regulator, 7812. The
input voltage should be a few volts higher to allow for voltage drops. Assume 20 volts. Lets also assume
that the load will draw 5amps. The power dissipation in the transistor will be Vce * Ic or (20-12)*8=40watt.
It may keep you warm in the Winter, but you will need a large heatsink with good thermal dissipation.
If you want to Boost the output current with a negative regulator, such as the 79xx series, then the circuit
is similar, but an NPN type power transistor is used instead.

MJ2955 +78XX Increasing Regulator Current circuit and explanation

Notes:
Although the 78xx series of voltage regulators are available with different current outputs, you can boost
the available current output with this circuit. A power transistor is used to supply extra current to the load
the regulator, maintaining a constant voltage. Currents up to 650mA will flow through the regulator, above
this value and the power transistor will start to conduct, supplying the extra current to the load. This should
be on an adequate heat sink as it is likely to get rather hot. Suppose you use a 12v regulator, 7812. The
input voltage should be a few volts higher to allow for voltage drops. Assume 20 volts. Lets also assume
that the load will draw 5amps. The power dissipation in the transistor will be Vce * Ic or (20-12)*8=40watt.
It may keep you warm in the Winter, but you will need a large heatsink with good thermal dissipation.
If you want to increase the output current with a negative regulator, such as the 79xx series, then the circuit
is similar, but an NPN type power transistor is used instead.

Source ::
http://www.mitedu.freeserve.co.uk/Circuits/Power/boosti.htm

12V 10Amp MJ2955 Switching Power Supply

The switching power supply provides 12 volts, at 10 amps, maximum, using a discrete transistor regulator with an op-amp functioning as a comparator in the feedback circuit.

With reference to the schematic, the front panel power-on light is not shown. There is no adjustable current limiter in this unit, although R1, R2, R3, Q2, R8, R9, C5 and Q4 set the current limit to approximately 10 amps. As you can see, the design is very similar to that of a linear power supply, except that L1, and D1 have been added, and U1 operates in a switching mode as a comparator with a small amount of hystersis. The switching frequency of this unit varies with the output current drawn by the load. This is an undesireable feature, which is why PWM regulators are used today. With a PWM regulator, the switching frequency is constant and will produce spurs only at known discrete frequencies rather than spurs at all frequencies. The Darlington-connected pass transistor block in the schematic is there twice (in parallel) for robustness. R4 in an internal trim-pot that can set the output voltage anywhere between 5 to 15 volts.
Read More Source :http://members.tripod.com/michaelgellis/power4.html
Thank You.

Power Amplifier OCL 50W by 741+2N3055+MJ2955(with PCB)

This is old circuit Power amp OCL, But easy circuit and very nice. To use for play music in your home. It low cost too.
It use IC 741 or LF351(good) and Transistor x 4 (2N3055+MJ2955+BD139+BD140) and little component. Power supply volt +35V/-35V and 3A for Mono, 5A for Stereo.

Circuit Power Amp OCL by 741+2N3055+MJ2955

PCB Power Amp OCL by 741+2N3055+MJ2955

MJ2955 Switching Power Supply 12V 10Amp

With reference to the schematic, the front panel power-on light is not shown. There is no adjustable current limiter in this unit, although R1, R2, R3, Q2, R8, R9, C5 and Q4 set the current limit to approximately 10 amps. As you can see, the design is very similar to that of a linear power supply, except that L1, and D1 have been added, and U1 operates in a switching mode as a comparator with a small amount of hystersis. The switching frequency of this unit varies with the output current drawn by the load. This is an undesireable feature, which is why PWM regulators are used today. With a PWM regulator, the switching frequency is constant and will produce spurs only at known discrete frequencies rather than spurs at all frequencies. The Darlington-connected pass transistor block in the schematic is there twice (in parallel) for robustness. R4 in an internal trim-pot that can set the output voltage anywhere between 5 to 15 volts.

Read More Source :http://members.tripod.com/michaelgellis/power4.html
Thank You.