Small Power Amplifier 8W 8Ω with TDA 2030

Although the TDA2030 can deliver 20 watts of output power, I deliberately reduced the output power to about 8 watts to supply 10 watt speakers. Input sensitivity is 200mV. Higher input levels naturally will give greater output, but no distortion should be heard. the gain is set by the 47k and 1.5k resistors. The TDA2030 IC is affordable and makes a good replacement amplifier for low to medium audio power systems. Incidentally, it is speaker efficiency that determines how "loud" your music is.

Small Power Amplifier Circuit diagram:

Parts:

R1-2=47ohmK 1/4W        
R3= 1.5Kohm 1/4W         
R4=1.2ohm /1W        
C1-5=1uF/25V
C2-6=100uF/25V
C3-7=100nF/63V
C4=220nF/63V
D1-2=1N4001
IC1=TDA 2030

Simple AC Power Current detector Circuit with LM1458

This circuit will detect power line currents of 250 mA or more without making electrical connections to the line. Current is detected by passing a line of alternating current through an inductive pickup (L1) as a screen diameter of 1 inch U-bolt wound with 800 turns # 30 – # 35 magnet wire.

The pickup could be made from rings of iron or other type of processor core that allows enough space to pass one of the AC lines through the center. Only one of the power line is the line or neutral must come from the center of the pickup to avoid the fields cancel.

I tested the circuit with a 2 wire extension cord that had separated the twin wires a small distance with an exacto knife to allow the U-bolt to encircle a single cable. The magnetic pick-up (U-bolt) produces about 4 millivolts peak for a series of alternating current of 250 mA, or AC load of around 30 watt

The signal from the pickup has grown about 200 times the output of pin op-amp 7, followed by the peak detected by diode and capacitor connected to pin 7. The second op-amp used as a reference point, which detects voltage increases above the drop pass.

The minimum mark required to cause the comparator output stage is a positive change of 800 mV peak around a power line 30-watt. The 1458 swing op-amp output in just a couple of times the ground so a voltage divider (1K/470) is used to reduce the voltage signal at about 0,7 volt.

An additional diode added in series with transistor base to ensure that off when the voltage op-amp is 2 volts. You can get a piece “of relay chatter if the AC load is close to the switching point so a larger load 50 W or higher recommended. The sensitivity can be increased by adding more becomes a pick-up

Simple 500W Audio Power Amplifier Circuit Diagram with Transistor

We take transistor MJL2194 and MJL2193 for drive output signal.so the amp has a capacity for enormous instantaneous current ability.

I think, it is useful for you to apply the circuit with your sound devices.

Circuit Functional
I use the -85 volt when the output current is supplied to the drive 350 to 340 very hot. Increase the output current, but it was too cold. The output to heat up faster than a normal open it. Sounds obvious, but sound quality is quite good.

I recomment it by turning out for the evening. If the drive is mounted on the metal part out.

I think simple. View full above, the observation that R 30 ohm then the voltage across the 0.86 V show that the new through its 29 mA if you add a file to / – 85 V, and suppose that the voltage across the component body. It was the same in both the R 30 ohm to get a very light 5 0.86 = 5.86 V and the current I will be 5.86/30 = 0.195 A = 195 mA, and the specification of mje340. mje350 get Ic (max) = 500 mA, so it is natural for it to heat up. Actually, it is not necessary to adhere to sync tr output should be interested in the following two tr power drive is better. For VR should be R300 .

5 8 Watt Audio Power Amplifier

This circuit use TA7222AP to amplifiers audio signal .The price only $0.99 and can provide 5.8 watt with Muting Control.Power supply can use for 8-12Vdc it is a good idea to use for car audio power amp , coin-op machine game, security system etc.

Fig 1. TA7222AP pin out

Pin	Name	Description
1	Vcc	Supply Voltage
2	RR	Ripple Reject
3	MC	Muting control
4	OP	AF Signal Input
5	FB	FB Filter
6	GA	Gain adjust
7	GND	Ground
8	GND	Ground
9	OP	AF Output
10	BS	BootStrap

Fig 2. schematic for 5.8 watt audio power amplifier

Soft Start For Switching Power Supply

Switching power supply whose output voltage is appreciably lower than its input voltage has an interesting property: the current drawn by it is smaller than its output current. However, the input power (UI) is, of course, greater than the output power. There is another aspect that needs to be watched: when the input voltage at switch-on is too low, the regulator will tend to draw the full current. When the supply cannot cope with this, it fails or the fuse blows. It is, therefore, advisable to disable the regulator at switch-on (via the on/off input). until the relevant capacitor has been charged. When the regulator then starts to draw current, the charging current has already dropped to a level which does not overload the voltage source.

The circuit in the diagram provides an output voltage of 5 V and is supplied by a 24 V source. The regulator need not be disabled until the capacitor is fully charged: when the potential across the capacitor has reached a level of half or more of the input voltage, all is well. This is why the zener diode in the diagram is rated at 15 V. Many regulators produced by National Semiconductor have an integral on/off switch, and this is used in the present circuit. The input is intended for TTL signals, and usually consists of a transistor whose base is accessible externally. This means that a higher switching voltage may be applied via a series resistor: the value of this in the present circuit is 22 kΩ. When the voltage across the capacitor reaches a level of about 17 V, transistor T1 comes on, whereupon the regulator is enabled.

Dual Power Supply 78xx 79xx

Many times the hobbyist wants to have a simple, dual power supply for a project. Existing powersupplies may be too big either in power output or physical size. Just a simple Dual Power Supply is required.For most non-critical applications the best and simplest choice for a voltage regulator is the 3-terminal type.The 3 terminals are input, ground and output.

The 78xx & 79xx series can provide up to 1A load current and it have onchip circuitry to prevent damage in the event of over heating or excessive current. That is, the chip simply shuts down rather than blowing out. These regulators are inexpensive, easy to use, and they make it practical to design a system with many PCBs in which an unregulated supply is brought in and regulation is done locally on each circuit board.

Circuit diagram:

Dual Power Supply Schematic Circuit diagram

This Dual Power Supply project provides a dual power supply. With the appropriate choice of transformer and 3-terminal voltageregulator pairs you can easily build a small power supply delivering up to one amp at +/- 5V, +/- 9V, +/- 12V, +/-15V or +/-18V. You have to provide the centre tapped transformer and the 3-terminal pair of regulators you want:7805 & 7905, 7809 & 7909, 7812 & 7912, 7815 & 7915or 7818 & 7918.

Note that the + and - regulators do not have to be matched: you can for example, use a +5v and -9V pair. However,the positive regulator must be a 78xx regulator, and the negative a 79xx one. We have built in plenty of safety into this project so it should give many years of continuous service.  The user must choose the pair he needs for his particular application.

Parts :

Transformer

This Dual Power Supply design uses a full wave bridge rectifier coupled with a centre-tapped transformer. A transformer with a power output rated at at least 7VA should be used. The 7VA rating means that the maximum current which can be delivered without overheating will be around 390mA for the 9V+9V tap; 290mA for the 12V+12V and 230mA for the 15V+15V. If the transformer is rated by output RMS-current then the value should be divided by 1.2 to get the current which can be supplied. For example, in this case a 1A RMS can deliver 1/(1.2) or 830mA.

Rectifier

We use an epoxy-packaged 4 amp bridge rectifier with at least a peak reverse voltage of 200V. (Note the part numbers of bridge rectifiers are not standardised so the number are different from different manufacturers.) For safety the diode voltage rating should be at least three to four times that of the transformers secondary voltage. The current rating of the diodes should be twice the maximum load current that will be drawn.

Filter Capacitor

The purpose of the filter capacitor is to smooth out the ripple in the rectified AC voltage. Theresidual amount of ripple is determined by the value of the filer capacitor: the larger the value the smaller the ripple.The 2,200uF is a suitable value for all the voltages generated using this project. The other consideration inchoosing the correct capacitor is its voltage rating. The working voltage of the capacitor has to be greater than thepeak output voltage of the rectifier. For an 18V supply the peak output voltage is 1.4 x 18V, or 25V. So we havechosen a 35V rated capacitor.

Regulators

The unregulated input voltage must always be higher than the regulators output voltage by at least 3V inorder for it to work. If the input/output voltage difference is greater than 3V then the excess potential must bedissipated as heat. Without a heatsink 3 terminal regulators candissipate about 2 watts. A simple calculation of the voltage differential times the current drawn will give the watts tobe dissipated. Over 2 watts a heatsink must be provided. If not then the regulator will automatically turn off if theinternal temperature reaches 150oC. For safety it is always best to use a small heatsink even if you do not think youwill need one.

Stability

C4 & C5 improve the regulators ability to react to sudden changes in load current and to preventuncontrolled oscillations.

Decoupling

The monoblok capacitor C2 & C6 across the output provides high frequency decoupling which keepsthe impedence low at high frequencies.

LED

Two LEDs are provided to show when the output regulated power is on-line. You do not have to use theLEDs if you do not want to. However, the LED on the negative side of the circuit does provide a minimum load tothe 79xx regulator which we found necessary during testing. The negative 3-pin regulators did not like a zeroloadsituation. We have provided a 470R/0.5W resistors as the current limiting resistors for the LEDs.

Diode Protection

These protect mainly against any back emf which may come back into the power supply when itsupplies power to inductive loads. They also provide additional short circuit protection in the case that thepositive output is connected by accident to the negative output. If this happened the usual current limiting shutdownin each regulator may not work as intended. The diodes will short circuit in this case and protect the 2 regulators.

Source :www.electronics-project-design.com