Schematic Diagram 4in1: 100W RMS Power Amplifier With VU, Power Supply and Tone Control

Part Lists

Active Components

• IC TDA 7294 : 1
• IC 7812 : 1
• IC LM3914 : 1
• Diode Zener 12V : 2
• IC 4558 : 1
• Diode 1N4148 : 1
• Rectifier Bridge Diode 6 A : 1
• LED : 11

Resistors

• 390 Ω – 1/4w : 1
• 680 Ω – 1/4w : 1
• 1K Ohm – 1/4w : 2
• 2k2 Ohm – 1/4w : 3
• 2k7 Ohm – 1/4w : 1
• 3k3 Ohm – 1/4w : 1
• 5k6 Ohm – 1/4w : 1
• 8k2 Ohm – 1/4w : 1
• 10K Ohm – 1/4w : 4
• 20K Ohm – 1/4w : 2
• 22K Ohm – 1/4w : 3
• 30K Ohm – 1/4w : 1
• 47k Ohm – 1/4w : 1
• 10R ohm – 1/4w : 1
• 56R Ohm – 2w : 1
• 2K2 Ohm – 2w : 2
• Potensiometer 50K Ohm : 3

Capacitors

• 100pF nonpolar capacitor disc / ceramic : 2
• 6n8F nonpolar polyester capacitor : 2
• 10nF nonpolar polyester capacitor : 2
• 100nF nonpolar polyester capacitor : 6
• 220nF nonpolar polyester capacitor : 1
• 2.2uF/63V electrolytic capacitor : 1
• 10uF/63V electrolytic capacitor : 5
• 22uF/63v electrolytic capacitor : 2
• 100uF/63V electrolytic capacitor : 2
• 4700uF/63V electrolytic capacitor : 2

100W RMS Power Amplifier PCB Layout

Component Placement

This is a single channel (mono) audio system. For stereo audio system, you need two similar circuit and make some changes such as: use higher transformer current, higher diode current, higher capacitor value for the power supply module. Use only one power supply. Use stereo potensiometer and connect to the two boards using cable.

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.

This is the circuit diagram of 0-60V / 0-2A variable power supply. Of course this circuit used to cover the voltage range from 0 to 60V and current from 0 to 2A. The maximum current can be increased, if we add the power transistors needed. Note the power output, just to cite one example, if delivery 2A 12V source to have a voltage drop of 48V with 2A consumption giving us a dissipation of 100 watts, is not a heating source, so, care.

Close attention should be paid to the way in which the two transistors BC327 circuit current protection, which work in saturation cutting work, another deals only activate an LED indicator on-load when the voltage drop lights output and will have to press the RESET button provided for the case. This will activate the output voltage again.

As already mentioned, this source has an intensity control, which disconnects the output voltage. This does not mean that supports the intersection of the (positive and negative) output cables. We must avoid this situation if possible as this will cause the destruction of transistors and other circuit components, it should be noted that we are dealing with respectable power.

For example: 5V and 2A output, this represents 65V – 5V = 60V which must be dissipated by the output transistors 2A, are talking about the power loss of 120 watts as a small “electric fire” this heat, more heat produced by 10W consumption advantage, they must evacuate 130W between the radiator and a fan that helps to lower the temperature that produces this “heater”, otherwise, you can imagine the result.

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.

This is the circuit diagram of 5V DC regulated power supply which featured with short circuit protection system. There are 2 kind of output that are regulated 5V DC with short circuit protection and without circuit protection. The main circuit is protected from any damage due to short-circuit in the additional power supply circuit by cutting off the derived supply voltage. The derived supply voltage restores automatically when shorting is removed. An indicator LED is utilized to show whether short-circuit exists or not.

Power Supply Block:
This circuit works just like the ordinary DC power supply adapter, in the main power supply circuit, 230V AC from main home electric source is stepped down by transformer X1 (230V AC primary to 0-9V, 300mA secondary), then rectified by a fullwave rectifier comprising diodes D1 through D4 with bridge arrangement (you may use a single bridge diode), filtered by capacitor C1 and regulated by IC 7805 to give regulated 5V DC output (O/P1).

Short-Circuit Protection Block:
Transistors SK100 and BC547 are used to derive the secondary output of around 5V (O/P2) from the main 5V supply (O/P1).

The working of this circuit is quite simple. When the 5V DC output from regulator IC 7805 is available, transistor BC547 conducts through resistors R1 and R3 and LED1. As a result, transistor SK100 conducts and short-circuit protected 5V DC output appears across O/P2 terminals. The green LED (LED2)? lows to indicate the same, while the red LED (LED1) remains off due to the presence of the same voltage at both of its ends.

When O/P2 terminals short, BC547 cuts off due to grounding of its base. As a result, SK100 is also cut-off. Thus during short-circuit, the green LED (LED2) turns off and the red LED (LED1) glows. Capacitors C2 and C3 across the main 5V output (O/P1) absorb the voltage fluctuations occurring due to short-circuit in O/P2, ensuring disturbance-free O/P1. The design of the circuit is refer to the relationship given below:

R_B = (H_FE ? V_S) / (1.3 ? I_L)

where,

R_B = Base resistances of transistors of SK100 and BC547
H_FE = 200 for SK100 and 350 for BC547
Switching Voltage V_S = 5V
1.3 = Safety factor
I_L = Collector-emitter current of transistors

Build the circuit on a general purpose PCB and mount in a general circuit box. Connect O/P1 and O/P2 terminals on the front panel of the cabinet. Also connect the mains power cord to feed 230V AC to the transformer. Connect LED1 and LED2 for visual indication.

This circuit has been tested by the author, the circuit that already built is shown on the following image:

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

This is variable DC power supply circuit, or we can call it adjustable DC power supply which give us a 1.2V-25V output voltage. The power supply schematic above is taken from the datasheet of regulator LM338K manufactured National Semiconductor. The circuit uses IC LM338K as the voltage regulator, so we will get the stable and regulated output. The regulator IC LM338K provides 5A output current max, and the voltage from 1.2 to 32V, it also featured the integrated thermal and short-circuit protection. Maximum voltage at input and output of the regulator is 35V .

The transformer current value depends your needs. For example, if you need 120W power output then you’ll need 5A transformer. 5A x 24V (full power) will give you 120W output power. Since this power supply circuit described to give us 1.2-25V DC output, then you must have transformer with 24V AC output.

For the diode, you have the choices whether use 4 diodes of single bridge diode. If you are have plan to use the PCB design in this post, then you have to use bridge diode. The value of diode is depend on the current value of transformer. For the example, if the circuit uses 3A transformer the you must use minimum 3A diode. The higher current value of diode, the price is more expensive of course…

The following images are the PCB layout design (bottom) and the component placement on the top. Don’f forget to use heatsink for LM338K to prevent overheat. I think every electronics hobbysts have high level of creativity, may be you’ll face some problems during the practice and you’ll solve the problem by yourself..

PCB Layout Design:

Component Placement:

Good luck…

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.

This is definitely an effective 4-output stage stabilized DC power supply unit for testing electronic circuits. It delivers very well regulated and stabilised output, that is important for most electronic circuits to provide good results. The circuit gives you an audio-visual indication if there is a short circuit in the PCB under test, so the power supply to the circuit “under test” could be cut-off instantly to protect the important components from damage.

The circuit gives you four different regulated DC outputs (12V, 9V, 6V and 5V) and an unregulated 18V DC output, that are selectable by way of rotary switch S2. The selected output is showed on the analogue voltmeter connected to the outputs rails.

The circuit works by using a typical 18V-0-18V, 500mA step-down transformer to deliver 18V AC. A rectifier diode comprising diodes D1 and D2 supplies 18V DC, that is smoothed by capacitor C1 and given towards the combination of regulator ICs (IC1 through IC4). The regulator ICs deliver fixed, regulated outputs of 12V, 9V, 6V and 5V, respectively, that are joined to the rotary switch contacts. This power supply is useful and effective for loads requiring up to 200mA current.

Complementary transistors T1 and T2 conduct in the event the power to the circuit is switched on. Full chosen supply voltage is obtainable at the collector of transistor T2, that is applied to power the load. LED3 signifies the presence of output voltage. The negative terminal of piezobuzzer PZ1 is joined to the output rail via LED2, so the piezobuzzer stays silent as its negative terminal is also at full supply voltage (selected). If there is a short circuit at the output, LED2 glows to activate the piezobuzzer.

A fuse-failure indicator distinguishes short circuit at the output and input failure. It includes a bicolour LED (LED1) and resistors R1 and R2. When power is available and also the fuse is intact, red and green halves of LED1 are effectively in parallel to output a yellowish light. When fuse fails, green LED goes off and red LED lights up to tell us fuse breakdown.

The circuit could be simply assembled on a general-purpose PCB. Use small heatsinks properly for all ICs to dissipate the IC temperature. The output voltage could be check out on a voltmeter. Assmble and mount the circuit inside a metal box / case with provisions for voltmeter, LEDs, rotary switch, and so on.

The 5V regulated power supply is apply 74LS series integrated circuits which has to be really precise and tolerant of voltage transients. These IC’s are simply damaged by brief voltage spikes. A fuse will blow when its electric current rating is exceeded, but requires several hundred milliseconds to respond. This circuit will react in a few microseconds, triggered when the output voltage exceeds the limit of the zener diode.

This circuit uses the crowbar process, where a thyristor is employed and short circuits the supply, causing the fuse to blow. This can take spot in just a few microseconds or less, and so provides a lot greater protection than an ordinary fuse. If the output voltage exceed 5.6V, then the zener diode will conduct, switching on the thyristor (all in a few microseconds), the output voltage is therefore reduced to 0 Volts and sensitive logic IC’s will probably be saved. The fuse will still take a few hundred milliseconds to blow but this isn’t significant now mainly because the supply to the circuit is already at 0 Volts and no harm is usually completed. The DC input towards the regulator needs to be some volts greater than the regulator voltage. In the case of a 5V regulator power supply, it’s suggested to use a transformer with secondary voltage of 8-10Vs AC.