Showing posts with label 1. Show all posts
Showing posts with label 1. Show all posts
Thursday, 23 March 2017
TDA7490 Audio Amplifier 2 x 25W 1 x 50W
TDA7490 general description:

The TDA7490 is a dual audio class D amplifier assembled in Flexiwatt 25 package; it is specially designed for high efficiency application mainly for TV and Home Stereo sets. TDA7490 Audio Amplifier 2 x 25W / 1 x 50W
TDA7490 features:
- 25W + 25W OUTPUT POWER:
- RL = 8Ω/4Ω; THD = 10%
- HIGH EFFICIENCY
- WIDE SUPPLY VOLTAGE RANGE (FROM
- ±10 TO ±25V)
- SPLIT SUPPLY
- TURN OFF/ON POP FREE
- ST-BY AND MUTE FEATURES
- SHORT CIRCUIT PROTECTION ACROSS
- THE LOAD
- THERMAL OVERLOAD PROTECTION
- EXTERNALLY SINCHRONIZABLE
- BRIDGE CONFIGURATION
TDA7490 sterio circuit diagram:
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| TDA7490 Audio Amplifier 2 x 25W / 1 x 50W circuit diagram |
TDA7490 mono circuit diagram:
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| TDA7490 Audio Amplifier 2 x 25W / 1 x 50W mono circuit diagram |
TDA7490 sterio circuit pcb:
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| TDA 7490 pcb layout |
Saturday, 14 January 2017
1 watt 10km FM Transmitter Circuit
In this article we learn about a 1 Watt FM Transmitter amplifier with a reasonably balanced design specified to boost a RF frequency in the 88 – 108 MHz spectrum.
It may be considered a fairly sensitive configuration when used with quality RF power amplifier transistors, trimmers and inductors. It involves a power amplification factor of 9 to 12 dB (9 to 15 times). At an input power of 0.1W the output may be well over 1W. It's advisable to choose T1 transistor on the basis of the fed voltage. Considering you possess a 12V power supply in that case using transistors like: 2N4427, KT920A, KT934A, KT904, BLX65, 2SC1970, BLY87. At 18 to 24V inputs you may want to use transistors such as: 2N3866, 2N3553, KT922A, BLY91, BLX92A. You could also consider using 2N2219 at 12V However that would yield just an output power of 0.4W at the fullest.

How to Calibrate this 1 watt fm power amp
Initially don't apply any sort of RF input, simply use the power and check with a meter the voltage at point 1. Calibrate R3 as you get the reading near about 0.7V. Use the antenna with a 2 x 100 Ω 0.5W resistors in parallel at the RF output. After this attach the rf source that may be supposed to boost and link up this RF input to the output.
Carefully set up C1 so as to extract the most optimal potential magnitude on the rf link. Next up, rotate R3 once more to acquire 0.7 V at point 1. Finally set up C5 and C6 for ensuring the highest output voltage (quite between 12V to 18V).
Verify the dissipation of T1′s heatsink, if you see it to be just fine switch off the power, isolate and pull of the 2 resistors of 100 Ω and connect back the antenna (make sure the the probe stays connected). Connect again the power and yet again allign C1, C5 and C6 for highest voltage read on the probe.
You could think of using a an ammeter for enabling reading the current incourse via T1. This must be restricted below 150mA at 12V and 100mA at 24V otherwise the transistor may well fry of. L2 and L3 coils must be installed at an angle of 90 degrees between the two. Don’t run the 1W rf fm amplifier in case you witness your TV set is getting jammed and perhaps the laws of the your country prohibits the use of such FM transmitters.BOM for the above 10km FM transmitter
R1 = 100 Ω
R2 = 2.2K Ω for 12 V and 4.7 kΩ for 24 V
R3 = 10 KΩ
R4 = 100 Ω
C1 = C5 = C6 = 10 – 60 pF
C2 = C4 = 1 nF
C3 = 10 uF
D1 = 1N4148
L1 = 20 turns of 0.2mm super enameled wire over R4
L2 = 7 turns of 0.8mm super enameled wire with 6mm diameter on air
L3 = 4 turns of 0.8mm super enameled wire with 7mm diameter on air
T1 = 2N4427, KT920A, KT934A, KT904, BLX65, 2SC1970, BLY87 (2N2219, output of 0.4W) at 12V
T1 = 2N3866, 2N3553, KT922A, BLY91, BLX92A at 24V
It may be considered a fairly sensitive configuration when used with quality RF power amplifier transistors, trimmers and inductors. It involves a power amplification factor of 9 to 12 dB (9 to 15 times). At an input power of 0.1W the output may be well over 1W. It's advisable to choose T1 transistor on the basis of the fed voltage. Considering you possess a 12V power supply in that case using transistors like: 2N4427, KT920A, KT934A, KT904, BLX65, 2SC1970, BLY87. At 18 to 24V inputs you may want to use transistors such as: 2N3866, 2N3553, KT922A, BLY91, BLX92A. You could also consider using 2N2219 at 12V However that would yield just an output power of 0.4W at the fullest.

How to Calibrate this 1 watt fm power amp
Initially don't apply any sort of RF input, simply use the power and check with a meter the voltage at point 1. Calibrate R3 as you get the reading near about 0.7V. Use the antenna with a 2 x 100 Ω 0.5W resistors in parallel at the RF output. After this attach the rf source that may be supposed to boost and link up this RF input to the output.
Carefully set up C1 so as to extract the most optimal potential magnitude on the rf link. Next up, rotate R3 once more to acquire 0.7 V at point 1. Finally set up C5 and C6 for ensuring the highest output voltage (quite between 12V to 18V).
Verify the dissipation of T1′s heatsink, if you see it to be just fine switch off the power, isolate and pull of the 2 resistors of 100 Ω and connect back the antenna (make sure the the probe stays connected). Connect again the power and yet again allign C1, C5 and C6 for highest voltage read on the probe.
You could think of using a an ammeter for enabling reading the current incourse via T1. This must be restricted below 150mA at 12V and 100mA at 24V otherwise the transistor may well fry of. L2 and L3 coils must be installed at an angle of 90 degrees between the two. Don’t run the 1W rf fm amplifier in case you witness your TV set is getting jammed and perhaps the laws of the your country prohibits the use of such FM transmitters.
R1 = 100 Ω
R2 = 2.2K Ω for 12 V and 4.7 kΩ for 24 V
R3 = 10 KΩ
R4 = 100 Ω
C1 = C5 = C6 = 10 – 60 pF
C2 = C4 = 1 nF
C3 = 10 uF
D1 = 1N4148
L1 = 20 turns of 0.2mm super enameled wire over R4
L2 = 7 turns of 0.8mm super enameled wire with 6mm diameter on air
L3 = 4 turns of 0.8mm super enameled wire with 7mm diameter on air
T1 = 2N4427, KT920A, KT934A, KT904, BLX65, 2SC1970, BLY87 (2N2219, output of 0.4W) at 12V
T1 = 2N3866, 2N3553, KT922A, BLY91, BLX92A at 24V
Monday, 19 December 2016
1 5 4 5V to 9V Converter Circuit Diagram
This is a Simple1.5.4.5V to 9V Converter Circuit Diagram. Build a Simple1.5.4.5V to 9V Converter Circuit Diagram.
1.5.4.5V to 9V Converter Circuit Diagram

1.5.4.5V to 9V Converter Circuit Diagram

Thursday, 15 December 2016
1 5V to 5V 12V DC DC Converter with LT1073
1.5V to 5V/12V DC/DC Converter with LT1073 Circuit


Small 1.5V to 5V or 12V DC/DC converter with LT1073 chip. The IC is available in three different versions, depending on output voltage. Two with fixed output voltage of 5V and 12V, and the most interesting that can be adjusted. The adjustment is done through a voltage divider with two resistors, of mass, output and Terminal 8, internally connected to the voltage comparator IC, which is responsible for stabilizing the output voltage.
Friday, 9 December 2016
Saturday, 3 December 2016
1 1 Regulator Handles Two Input Voltages Circuit Diagram
Regulator Handles Two Input Voltages circuit in Fig 1 supplies both 3.3 and 5V to transitional circuits that employ both the new 3.3V and older 5V devices. Additionally, because the regulator accepts either 3.3 or 5V inputs, you could plug it into either a new 3.3V system or an old 5V system.The circuit consists of two sections: a dc/dc converter and a double-pole, double-throw (dpdt) switch. The dpdt switch comprises a pair of dual n-channel MOSFETs (Q2 and Q3) and their associated high-side drivers.
Upon power-up, the comparator in IC2 determines the state of the circuit. The comparator’s output, IC2 pin 6, goes to the input of the MOSFET driver, IC1. The driver internally generates a gatedrive voltage 8.8V above the device’s supply voltage. This high voltage drives the appropriate MOSFETs in Q2 and Q3.
IC2 is also the heart of a flying-capacitor, buck/boost dc/dc converter. Unlike other switching-regulator schemes, this topology needs no transformers. Transistor Q1 controls this section’s output voltage, VS. When VIN is at 5V, Q1 is off, forcing the section to operate as a step-down converter. In this mode, the section produces 3.3V, which goes to the output through Q3B. Also in this mode, 5V power goes directly through Q2A, and Q2B and Q3A are both off.
Upon power-up, the comparator in IC2 determines the state of the circuit. The comparator’s output, IC2 pin 6, goes to the input of the MOSFET driver, IC1. The driver internally generates a gatedrive voltage 8.8V above the device’s supply voltage. This high voltage drives the appropriate MOSFETs in Q2 and Q3.
IC2 is also the heart of a flying-capacitor, buck/boost dc/dc converter. Unlike other switching-regulator schemes, this topology needs no transformers. Transistor Q1 controls this section’s output voltage, VS. When VIN is at 5V, Q1 is off, forcing the section to operate as a step-down converter. In this mode, the section produces 3.3V, which goes to the output through Q3B. Also in this mode, 5V power goes directly through Q2A, and Q2B and Q3A are both off.

When VIN is 3.3V, IC1 turns on Q1, shorting out the 140-kΩ resistor and forcing the dc/dc-converter section into step-up mode. In this mode the converter section generates 5V at VS, powering the 5V output via Q2B. Also in this mode, 3.3V goes directly from the circuit’s input to the output via Q3A. Q2A and Q3B are both off.No-load quiescent current consumption is approximately 500 μA.
Lower-frequency converters would reduce power consumption at the expense of a larger inductor. The efficiency of the dc/dc-converter section is 73% in either mode. But because this power accounts for only half of the circuit’s output power, the circuit’s overall efficiency is approximately 80% with VIN=3.3V and 86% with VIN=5V.
Lower-frequency converters would reduce power consumption at the expense of a larger inductor. The efficiency of the dc/dc-converter section is 73% in either mode. But because this power accounts for only half of the circuit’s output power, the circuit’s overall efficiency is approximately 80% with VIN=3.3V and 86% with VIN=5V.
Tuesday, 29 November 2016
Low Cost 1 5 to 9 Volts Inverter
This electronic circuit project is very interesting and low-cost electronic project, some electronic circuits we need a 9 volts power supply, but we need to use a battery if that device is mobile. In many cases we don’t have a 9 volts battery or we don’t have enough space to put a 9 volts battery inside the device, so this case we can use a this inverter circuit that will convert 1.5v to 9v to take the place of those expensive 9v batteries.
1.5 to 9 Volts Inverter Circuit Diagram:

The input voltage for this inverter can be from 1.5 volts, up to 4.5 volts. When no current is being drawn from the output the current is less than 10mA.
This inverter circuit is very simple requiring few components, but it can be used only for projects that require low current. The L1 coil must have 60 turns on a 10 mm ferrite slug 15 mm long, using a 0.25 mm diameter enameled wire.
1.5 to 9 Volts Inverter Circuit Diagram:

The input voltage for this inverter can be from 1.5 volts, up to 4.5 volts. When no current is being drawn from the output the current is less than 10mA.
This inverter circuit is very simple requiring few components, but it can be used only for projects that require low current. The L1 coil must have 60 turns on a 10 mm ferrite slug 15 mm long, using a 0.25 mm diameter enameled wire.
Tuesday, 15 November 2016
Adjustable Symmetric 1 to 24VDC 1A Power Supply
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
- 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
Thursday, 1 September 2016
Download Wiring diagram 2 humbuckers 1 volume 1 tone 3 way switch
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2 humbuckers/5-way lever switch/1 volume/1 tone/06, Guitar wiring diagram with 2 humbuckers, 5-way 4-pole lever switch, one volume and one tone control. same 5 pickup configurations as the prs 5 way rotary switching..
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Mod garage: strat-prs crossover wiring | premier guitar, Fig. 1 — wiring diagram courtesy of singlecoil.com. exactly 10 years ago, i wrote my first column for the publication that evolved into premier guitar, and as you can.
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