Saturday, August 31, 2013

Simple Field Strength Meter

This Field Strength Meter is simple and also quite sensitive. It uses an ordinary digital voltmeter to measure RF signal strength up to a few hundred MHz.



Simple Field Strength Meter Circuit diagram:




Parts List:

1 OA91 Germanium Diode
1 3.3M Resistor
1 100p Capacitor
L1 7 turns on a 1/4 inch former (suitable for around 100MHz)

Notes:

The multimeter should be set to the lowest dc volts range for maximum sensitivity. This is normally 200mV DC for most meters. The circuit works well at VHF (around 100MHz) and was quite pleased with the results. L1 was 7 turns on a quarter inch former with ferrite slug. This covered the UK FM band.

A digital multimeter, as opposed to an analogue signal meter offers several advantages in this circuit. First, the impedance of a digital meter is very high, around 10Meg/Volt on most meters. This does not shunt the tank circuit unduly. Second, compared to an analogue meter, very slight differences in signal strength can be more easily observed. Thirdly,a digital meter will have better linearity, responding well to both weak and stronger signals.
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Thursday, August 15, 2013

Active band reject filter Circuit

A filter with a band-reject characteristic is frequently referred to as a notch filter. A typical circuit using a µ 741 is the unity-gain configuration for this type of active filter shown. The filter response curve shown is a second-order band-reject filter with a notch frequency of 3 kHz. The resulting Q of this filter is about 23, with a notch depth of - 31 dB.Although three passive networks are used in this application, the operational amplifier has become a sharply tuned low-frequency filter without the use of inductors or large-value capacitors.

 Active band-reject filter Circuit Diagram

 Active band-reject filter Circuit Diagran

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Tuesday, August 13, 2013

TV Protect Circuit Dead or Damaged

Television set equipped with a circuit protector, then there are several possibilities that could occur if there is a problem on one of the circuits. Protect circuit horizontal part - When turned on the horizontal plane will live for a while, but then died again. At the time of death when measured on the horizontal driver indicates that no drive signal. If the power jack unplugged then try to turn on again then repeated a similar incident will happen again. But if if the base of the transistor or transistor try to open removable drive signal was viable.

Protect circuit of microcontroll - If checked the voltage at pin microcontrol power on-off control, power control is turned on when the plane going "on" for a while then back "off". If you unplugged the power jack will power "on" again, but briefly and then keep coming back "off". On certain models sometimes die when the aircraft was marked with the blazing LED indicators blink. Protect circuit tube - aircraft can be turned on but a dark raster. 
IC protek protek rusak
Protect IC

Tested voltage raster screen can be raised to normal flame or flame a horizontal line. Protect circuit the power supply - if enabled aircraft B + voltage of power supply there for a while but then lost or drops. Or the power supply voltage drops and there is but little rocking voltage, which is caused due to power supply to the death over and over again and again. There are models of televisions that do not use the protector system at all, there is only one system that uses a surge protector, but there are also some systems which use a surge protector as well. System protectors are made available for specific purposes. Keep track of the damage that led to protect circuit is sometimes difficult, because it always turns itself off the plane before we can make measurements. By getting to know a wide range of system protectors and understand how it works it will help overcome these difficulties.

Various kinds of protectors television system:
  • Protectors x-ray
  • Vertical Protectors
  • Protectors B + over current (OCP)
  • Protectors B + over voltage (OVP)
  • ABL Protectors
  • Supply voltage surge protector (if short or broken)
  • Protectors white balance
  • Protectors circuit power supply (SMPS)

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Sunday, August 11, 2013

Simple Output limiter Circuit Diagram

Simple Output-limiter Circuit Diagram HA-5190 is rated for ±5 V output swing, and saturates at ±7 V. As with most op amps, recovery from output saturation is slow compared to the amplifier`s normal response time. Some form of limiting, either of the input signal or in the feedback path, is desirable if saturation might occur. The circuit illustrates a feedback limiter, where gain is reduced ifthe output exceeds ± ( Vz + 21j-). A 5-V zener with a sharp knee characteristic is recommended. 

Simple Output-limiter Circuit Diagram

Simple Output-limiter Circuit Diagram

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Friday, August 9, 2013

Mobile Phone and iPod Battery Charger

Charge your iPod without connecting it to a computer!

Using the USB port on your computer to charge your player’s batteries is not always practical. What if you do not have a computer available at the time or if you do not want to power up a computer just for charging? Or what if you are traveling? Chargers for Mobile Phones iPods and MP3 players are available but they are expensive and you need separate models for charging at home and in the car.

This charger can be used virtually anywhere. While we call the unit a charger, it really is nothing more than a 5V supply that has a USB outlet. The actual charging circuit is incorporated within the iPOD or MP3 player itself, which only requires a 5V supply. As well as charging, this supply can run USB-powered accessories such as reading lights, fans and chargers, particularly for mobile phones.

The supply is housed in a small plastic case with a DC input socket at one end and a USB type "A" outlet at the other end, for connecting to Mobile Phone, an iPod or MP3 player when charging. A LED shows when power is available at the USB socket. Maximum current output is 660mA, more than adequate to run any USB-powered accessory.

Pictures, PCB and Circuit Diagram:

 Circuit_of_Mobile_Phone_Charger Front View Of Mobile Phone and iPod Battery Charger Circuit

 

Circuit_of_Mobile_Phone_Charger1 Bottom View Of Mobile Phone and iPod Battery Charger Circuit

PCB of Mobile Phone Charger PCB Layout Of Mobile Phone and iPod Battery Charger Circuit

Mobile Phone and iPod Battery Charger Circuit Mobile Phone and iPod Battery Charger Circuit Diagram

Parts Description
P1 1K
R1 1R-0.5W
R2 1R-0.5W
R3 1R-0.5W
R4 1K
R5 560R
R6 10R-0.5W
R7 470R
C1 470uF-25V
C2 100nF-63V
C3 470pF
C4 100uF-25V
D1 1N5404
D2 1N4001
D3 1N5819
D4 5.1V-1W Zener Diode
D5 5mm. Red LED
L1 220uH
S1 USB A Type Socket
SW1 On/Off Switch
IC1 MC34063A

Specifications:
Output voltage ----------------------5V
Output current ---------------------660mA maximum for 5V out
Input voltage range ------------------9.5V to 15V DC
Input current requirement ----------500mA for 9V in, 350mA for >12V input
Input current with output shorted--- 120mA at 9V in, 80mA at 15V in
Output ripple ------------------------14mV (from no load to 660mA)
Load regulation ----------------------25mV (from no load to 660mA)
Line regulation ----------------------20mV change at full load from 9 to 18V input
No load input current ----------------20mA
(The specification for the computer USB 2.0 port requires the USB port to deliver up to 500mA at an output voltage between 5.25V and 4.375V).

The circuit is based around an MC34063 switch mode regulator. This has high efficiency so that there is very little heat produced inside the box, even when delivering its maximum output current. The circuit is more complicated than if we used a 7805 3-terminal regulator but since the input voltage could be 15V DC or more, the voltage dissipation in such a regulator could be 5W or more at 500mA. and 5W is far too much for a 7805, even with quite a large heatsink. Credit for this circuit goes to SiliconChip, A wonderful electronics magazine.

Source :www.extremecircuits.net

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Wednesday, August 7, 2013

50W Offline Switching Power supply Circuit Diagram

The schematic shows a 50W power supply with a 5-V 10-A output. It is a fly back converter operating in the continuous mode. The circuit features a primary side and secondary side controller will full-protection from fault conditions such as over current. After the fault condition has been removed, the power supply will enter the soft-start cycle before recommencing normal operation.

50W Offline Switching Power supply Circuit Diagram

50W Offline Switching Power supply Circuit Diagram

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Monday, August 5, 2013

Wiring Diagram

Cat5e Wiring Diagram on Network Cable Use Either 568a Or Most Common 568b Wiring On Both Ends
Network Cable Use Either 568a Or Most Common 568b Wiring On Both Ends.


Cat5e Wiring Diagram on How To Make A Cat5e Network Cable   Miscellaneous Items
How To Make A Cat5e Network Cable Miscellaneous Items.


Cat5e Wiring Diagram on Diagram Of Correct Color Alignment For Making Cat5e Network Wall Jack
Diagram Of Correct Color Alignment For Making Cat5e Network Wall Jack.


Cat5e Wiring Diagram on Mica   Machine Information Consulting Alliance    Windows Xp Help
Mica Machine Information Consulting Alliance Windows Xp Help.


Cat5e Wiring Diagram on Cross Over Cable Just Uses The Wiring Configuration From Each
Cross Over Cable Just Uses The Wiring Configuration From Each.


Cat5e Wiring Diagram on How To Wire A Cat5  Eia 568 A   Cable
How To Wire A Cat5 Eia 568 A Cable.


Cat5e Wiring Diagram on 78 Responses To How To Install An Ethernet Jack For A Home Network
78 Responses To How To Install An Ethernet Jack For A Home Network.


Cat5e Wiring Diagram on Fs  Asus P8p67 Motherboard And Amd Xfx 6950
Fs Asus P8p67 Motherboard And Amd Xfx 6950.


Cat5e Wiring Diagram on Cat 5e Wiring Diagram
Cat 5e Wiring Diagram.


Cat5e Wiring Diagram on Cat5e Cable  Cat 5e Cables  Patch Cords
Cat5e Cable Cat 5e Cables Patch Cords.


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Saturday, August 3, 2013

Cat7 Cables Unshielded Twisted Pairethernet Wiring

Ethernet Wiring on Crossover Ethernet Cable
Crossover Ethernet Cable.


Ethernet Wiring on Figure  3    Tie Eia T568 Ethernet Wiring Standards
Figure 3 Tie Eia T568 Ethernet Wiring Standards.


Ethernet Wiring on Cat7 Cables  100 Ohm Utp  Unshielded Twisted Pair  Ethernet Wiring
Cat7 Cables 100 Ohm Utp Unshielded Twisted Pair Ethernet Wiring.


Ethernet Wiring on Switched Ethernet Modern Ethernet Implementations Often Look Nothing
Switched Ethernet Modern Ethernet Implementations Often Look Nothing.


Ethernet Wiring on Figure 4   Wiring Diagram For An Ethernet Crossover Cable
Figure 4 Wiring Diagram For An Ethernet Crossover Cable.


Ethernet Wiring on Detailed Graph For Coloring Scheme  Eia 568  Is
Detailed Graph For Coloring Scheme Eia 568 Is.


Ethernet Wiring on Diagram Of Correct Color Alignment For Making Cat5e Network Cable
Diagram Of Correct Color Alignment For Making Cat5e Network Cable.


Ethernet Wiring on Category 5 Wiring Scheme   Straight Through Cable Vs  Crossover Cable
Category 5 Wiring Scheme Straight Through Cable Vs Crossover Cable.


Ethernet Wiring on Do It Yourself  Roll Your Own Network Cables
Do It Yourself Roll Your Own Network Cables.


Ethernet Wiring on Beginnercode Com    Connecting Network Cable Ends
Beginnercode Com Connecting Network Cable Ends.


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Thursday, August 1, 2013

Analog Signal Transmission Circuit Through DC Supply Line

If the sensor system need an active supply, we can use only a single pair of cable to carry both the power supply and the output signal. Not only simplify the wiring, converting analog voltage level to frequency modulated pulse improve the noise immunity as well. This is the figure of the circuit;


The diode is employed to prevent the capacitor voltage to be discharged when the transistor is grounding the supply voltage source to send a zero pulse. If the sensor or input system need a supply, we can tap the power from the 1uF capacitor, as long as it need only small current. [Circuit diagrams  source: Microchip Application Note]
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