Simple and cheap, the circuit built based on well-known IC regulator LM317 with current booster of power transistor 2N3782. Don’t forget to add heatsink especially for power transistor 2N3782.

A switching power supply is a type of power supply that uses electronic switches to control the flow of electrical energy. Unlike linear power supplies, which regulate the output voltage by dissipating excess energy as heat, switching power supplies are more efficient because they switch the input voltage on and off at a high frequency.

Switching power supplies are widely used in electronic devices, computers, telecommunications equipment, LED lighting, and other applications where efficiency, size, and weight are critical considerations. However, they can introduce electrical noise, and careful design is required to minimize electromagnetic interference (EMI).

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120W Power Amplifier Part List

Transistors

• 2N3055 (substitution: MJ15003 or 2N3772) : 2
• MJ2955 (substitution: MJ15004 or 2N3771) : 2
• TIP42 : 2
• TIP41 : 1
• 2SC2229 or 2SC2230 or C1573 : 2
• A1015 or A872 or A733 : 2

Capacitors

• 100uF/50V electrolytic capacitor: 2
• 470nF (474) nonpolar polyester capacitor: 1
• 100pF (101) nonpolar ceramic capacitor : 2
• 470pF (471) nonpolar ceramic capacitor : 2
• 10pF nonpolar ceramic capacitor : 2
• 100nF (104) 100V nonpolar polyester capacitor : 2

Resistors

• 0.33 Ω (5W) : 4
• 10 Ω to (1W) – brown, black, black : 1
• 100 Ω (1W) – brown, black, brown : 2
• 33 Ω (1/4W) – orange, orange, black : 1
• 150 Ω (1/4W) – brown, green, brown : 3
• 10KΩ (1/4W) – brown, black, orange : 1
• 1KΩ (1/4W) – brown, black, red : 1
• 4.7KΩ (1W) – yellow, violet, red : 1
• 68KΩ (1/4W) – blue, gray, orange : 1
• 56KΩ (1/4W) – green, blue, orange : 1
• 33KΩ (1/4W) – orange, orange, orange : 1
• 3.3KΩ (1/4W) – orange, orange, red : 2

Diodes

• 3A Diode 1N5404 : 2
• 1A Diode 1N4007 : 3
• Zener diodes between 20 and 24 volts : 1

Others

• 3A fuse
• small 3-pin (GP) connector
• large 6-pin connector (Molex)
• aluminum heatsink
• potentiometer of 20K if you want to add volume control

120W Power Amplifier PCB Layout Design

Bottom PCB Layout (Copper)

Top PCB Layout and Component Placement

How to mount the transistors to the aluminium heatsink, see below image:

The points are: prevent circuit shortage, use proper isolator and use thermal compound for maximum heat spreading to the heatsink. Use mica between the transistor and the heatsink.

Power Supply Circuit for 120W Power Amplifier

Power Supply Bottom PCB Layout

Power Supply Top PCB Design

Power Supply Part List

• Transformer for the mono amplifier should be 35 + 35 volts AC with a minimum of 3 amps. If the stereo channel, the amperage should be doubled.
• Capacitors of 4700 uF/63V: 4
• Diode bridge (rectifier) ​​of 15 Amps: 1

120W Power Amplifier Wiring Connection

This is how to connect the amplifier module to the speaker, power supply and audio input. And connect the power supply module to the transformer.

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Powered with solar panel, the circuit will give you 5V pure regulated DC voltage. This solar cell power supply circuit is made up of an oscillator transistor as well as a regulator transistor. The solar panel charges the battery when sunlight is bright enough to generate a voltage above 1.9v. A diode is necessary between the panel and also the battery as it leaks about 1mA from the battery when it really is not illuminated. The regulator transistor is intended to limit the output voltage to 5v. This voltage will likely be maintained over the capability of the circuit, which is about 10mA.

The oscillator transistor should be a high-current sort as is is turned on for an extremely limited time period to saturate the core of the transformer. This energy is then released as a high-voltage pulse. These pulses are then passed to the electrolytic and appear as a 5v supply, having a capability of about 10mA. If the electric electric current is increased to 15mA, the voltage drops to about 4v.

The transformer is wired to ensure that it gives POSITIVE feedback. The transistor turns on via the 1k resistor and this produces expanding flux inside the core. The flux cuts the turns of the secondary winding and produces a voltage that ADDS to the turn on voltage and also the transistor is turned on A lot more. The transistor gets totally turned ON as well as the electric current via the main becomes a maximum. The core becomes saturated and though the flux is really a maximum, it really is not expanding flux and therefore the secondary produces no voltage (only the voltage and electric current supplied by the battery).

The voltage and electric current into the base of the transistor is decreased, and this cuts down the electric current via the main. The flux now begins to collapse and this produces a voltage in the secondary of an opposite polarity. This turns the transistor OFF and also the magnetic flux collapses shortly and produces a high voltage. This voltage is passed via the diode and charges the electrolytic. The circuit operates at approx 50kHz as well as the pulses shortly charge the electrolytic.

The 15k resistor has a 3k3 “trimmer” resistor to allow you to adjust the output to specifically 5v or slightly above 5v. Microcontrollers will operate up to 5.5v but some will freeze at 5.6v, so be careful. The output voltage is monitored at the join of the 15k resistor (and 3k3) as well as the 2k2 resistor. The voltage at this point is precisely 0.63v (630mV) and at this voltage, the regulator transistor turns ON and robs the oscillator transistor with “turn-on” voltage.

When a load is placed on the output of the circuit, the voltage across the electrolytic drops as well as the regulator turns off slightly. This permits the oscillator transistor to operate “harder” and send pulses of energy to the electrolytic to charge it. If the load is removed, the electric current consumption of the circuit is about 3.5ms. This may be the quiescent current in the circuit.

The output electric current is limited as every mA needs about 5mA from the battery. On 15mA output, the current needed from the battery is about 75mA. That is why we need a high-current capability transistor for the oscillator. A BC 547 transistor won’t function, as it really is not capable of passing a high electric current.

The solar panel will deliver about 10 – 15mA on bright sunlight, so any load on the output should be as small as possible. An example is information logging, exactly where the micro is active for short periods of time, then goes into “sleep” mode.

5V Regulated Solar Cell Power Supply circuit source: talkingelectronics.com

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This is the circuit diagram of adjustable symmetric 1 to 24VDC, 1A Power Supply. This power supply give dual output positive and negatif output, you can adjust both positif and negative output (+1 to +24VDC and -1 to -24VDC). This kind of power supply also known as dual polarity power supply or splitted power supply which give positive anf negatif output.

This power supply can be used for universal usage, which required not more than 1A DC current. Please take a note that you should adjust the output voltage using general multimeter or DC voltmeter before use this power supply to protect the supplied devices.

Circuit Features:

• Low cost universal symmetric power supply
• Just add a suitable transformer and a heatsink
• Ideal for e.g. op-amp applications, amplifiers, …
• Trimmers can be replaced by potmeters to allow continuous adjustment of output voltage
• LED output indicators

Circuit Specifications:

• Positive and negative output adjustable between 1.2 and 24VDC
• Output current: up to 2 x 1A continuous (with suitable heatsink)
• Max. input voltage: 2 x 24VAC
• Very good line and load regulation
• Low ripple
• Short circuit protection
• Thermal protection

Circuit Manual of Adjustable Symmetric 1 to 24VDC, 1A Power Supply:

Adjustable Symmetrical Power Supply

1 file(s) 1.45 MB

Download Circuit Manual

Kit Version:
This circuit available in kit version by valleman, you may purchase this kit online.

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Above circuit diagram is a easy, simple and cheap switching voltage regulator which has capability to deliver adjustable voltage output range of 1.8V to 32V and static electric current of 3A. This regulator use adjustable regulator IC of LM317HV and a power PNP transistor of 2N3792.

The LM317HV is adjustable 3-terminal positive voltage regulators capable of supplying in excess of 1.5A over a 1.2V to 57V output range. This electronic component exceptionally easy to use and require only two external resistors to set the output voltage. Further, both line and load regulation are better than standard fixed regulators. Also, the LM317HV is packaged in standard transistor packages which are easily mounted and handled.

LM317HV Features:

• Adjustable Output Down to 1.2V
• Specified 1.5A Output Current
• Line Regulation Typically 0.01%/V
• Load Regulation Typically 0.1%
• Current Limit Constant with Temperature
• 100% Electrical Burn-in
• Eliminates the Need to Stock Many Voltages
• Standard 3-lead Transistor Package
• 80 dB Ripple Rejection
• Output is Short-circuit Protected
• P⁺?Product Enhancement Tested

Circuit Notes:

• C1 and C4 must be solid tantalum capacitor type to get the best output quality.
• L1: CORE-ARNOLD A.254168.2 60 TURNS

Download LM317HV datasheet for project reference.

LM317HV Datasheet

1 file(s) 2.61 MB

Download Datasheet

The post 3A Switching Voltage Regulator based LM317HV appeared first on Circuit Schematic Diagram.

Components List:

Circuit Description:
This is an easy to make power supply that has reliable, clear and regulator 0 to 28 Volt 6/8 Amp output voltage. By making use of two 2N3055 transistor, you’ll get two times the amount of electric current.

Although the 7815 power regulator may kick in on short circuit, overload and thermal overheating, the fuses in the main section of the transformer and the fuse F2 at the output will safe your power supply. The rectified voltage of: 30 volt x SQR2 = 30 x 1.41 = 42.30 volt measured on C1. So all capacitors should be rated at 50 volts. Caution: 42 volt will be the voltage that could be on the output if 1 of the transistors ought to blow.

P1 lets you ‘regulate’ the output voltage to something in between 0 and 28 volts. The LM317 lowest voltage is 1.2 volt. To have a zero voltage on the output I’ve place 3 diodes D7,D8 and D9 around the output with the LM317 towards the base with the 2N3055 transistors. The LM317 optimum output voltage is 30 volts, but using the diodes D7,D8 & D9 the output voltage is approx 30v – (3x 0.6v) = 28.2volt.

Adjust your build-in voltmeter using P3 and, of course, a fine digital voltmeter is better solution.

P2 will let you to control the limit with the optimum available electric current in the output +Vcc. When utilizing a 100 Ohm / 1 watt varistor the current is limited to approx. 3 Amps @ 47 Ohm and +- 1 Amp @ 100 Ohms.

6A / 0-28V Variable Power Supply source:
http://users.belgacom.net/hamradio/homebrew.htm

The post 6A / 0-28V Variable Power Supply appeared first on Circuit Schematic Diagram.

At times, power from a wall socket is neither clean nor uninterruptible. Many abnormalities such as blackouts, brownouts, spikes, surges, and noise can occur. Under the best conditions, power interruptions can be an inconvenience. At their worst, they can cause loss of data in computer systems or damage to electronic equipment.

It is the function of an Uninterruptible Power Supply (UPS) to act as a buffer and provide clean, reliable power to vulnerable electronic equipment. The basic concept of a UPS is to store energy during normal operation (through battery charging) and release energy (through DC to AC conversion) during a power failure.

UPS systems are traditionally designed using analog components. Today these systems can integrate a microcontroller with AC sine wave generation, offering the many benefits.

The PIC17C43 microcontroller handles all the control of the UPS system. The PIC17C43 is unique because it provides a high performance and low cost solution not found in other microcontrollers.

PIC17C43 Microcontroller Benefits:

• High Quality Sine Wave – High throughput allows for high quality output
• Flexibility – core control features and operations can be changed with software modifications only
• Transportability of Design
• Variable Loop Response
• Digital Filtering
• Parts and Complexity Reduction
• Peripheral Integration
• Ease of Interfacing
• Testability
• Time to Market

Download the reference design of Uninterrupted Power Supply with PIC:

UPS with PIC17C43 Microcontroller

1 file(s) 2.41 MB

Download the file here

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Above schematic diagram is the circuit of the variable desktop power supply. Regulator IC LM317T is set up in its standard application. Diode D1 protects against polarity reversal and capacitor C1 is an additional buffer. The green LED (LED1) signifies the status of the power input. Diode D2 keeps the output voltage from increasing above the input voltage when a capacitive or inductive load is hooked up at the output. Similarly, capacitor C3 eliminates any residual ripple.

Connect a common digital voltmeter in parallel with the output leads to precisely set the wanted voltage with the support of variable resistor / potensiometer VR1. It is possible to also work with your digital multimeter in case the digital voltmeter isn’t around. Switch on S1 and set the needed voltage through potensiometer VR1 and start reading it on the digital voltmeter. Now the power supply is all set to be used.

The circuit could be built on a general purposed Printed Circuit Board (PCB). Refer refer to the following picture for the pin configuration of LM317, just before soldering it on the PCB.

When the circuit already build, then enclose the circuit inside a metallic box, the suggested power supply box shown below:

Then open up the case of the desktop computer and hook up the input line of is circuit to a free available (hanging) four-pin drive power connector of the SMPS properly.

The post 1 – 9V Variable Desktop Power Supply appeared first on Circuit Schematic Diagram.

This power supply unit can be used for general purposes, as long as the maximum specifications are taken into account.

Power Supply Technical Data:

• Short circuit protected
• Overload protected
• Output voltage: adjustable 3 to 30V stabilized.
• Output current: max. 3A
• Output ripple voltage: 0.5mV.
• Input: 9 to 30V transformer, depending on the desired output

Download the manual of this circuit include the schematic and part list from the following link:

3-30V 3A power supply circuit manual

1 file(s) 673.66 KB

Download Circuit Manual

Kit Version:

The post 3V-30V/3A Adjustable Regulated Power Supply appeared first on Circuit Schematic Diagram.

The schematic diagram:

Components list:

R1 : 100 ohm at 25 deg Celcius
R2 : 1 ohm – 1W
R3 : 10 ohm – 1/4W
R4 : 100K ohm – 1/4W
R5 : 0.33 ohm – 1W
R6 : 10K ohm – 1/4W
R7 : 390 ohm – 2W
R8 : 22K ohm – 10W
R9 : 68 ohm – 1/4W
R10 : 10 ohm – 1/2W
R11 : 3.3 ohm – 1/2W
RL : 5 ohm – 10W
C1 : 22 nF/400V
C2 : 470 uF/250V
C3 : 470 uF/16V
C4 : 220 pF/100V
C5 : 470 pF/500V
C6 : 2.2 nF/500V
C7 : 270 pF/500V
C8 : 39 pF/500V
C9 : 11000 uF/6.3V
C10 : 100 uF/16V
C11 : 0.047 uF/10V
L1 : 25 uH
D1 : IN4937
D2 : MBR1035
T1 : Lp=9 mH, n=1:15
T2 : 50 uH, n=1:3
F1 : Fuse 1A/SB
M1 : Diode Bridge
Q1 : BUZ80A/IXTP4N80 (220V AC)
Q1 : GE IRF823 (110V AC)

The schematic shows a 50-W power supply with a 5-V 10-A output. It truly is a flyback converter operating inside the continuous mode. The offline switching power supply circuit has functionality of a primary side and secondary side controller will full-protection from fault factors for example, overcurrent. When the error condition has been removed, the power supply will enter the soft-start cycle prior to recommencing normal operation.

The post 5V/10A 50W Offline Switching Power Supply appeared first on Circuit Schematic Diagram.