Schematic Diagram

Tuesday, September 2, 2014

Mobile Cellphone Battery Charger Circuit

Charging of the mobile phone, cellphone battery is a big problem while traveling as power supply source is not generally accessible. If you keep your cellphone switched on continuously, its battery will go flat within five to six hours, making the cellphone useless.A fully charged battery becomes necessary especially when your distance from the nearest relay station increases. Here’s a simple charger that replenishes the cellphone battery within two to three hours. Basically, the charger is a current-limited voltage source. Generally, cellphone battery packs require 3.6-6V DC and 180-200mA current for charging.These usually contain three NiCd cells, each having 1.2V rating. Current of 100mA is sufficient for charging the cellphone battery at a slow rate. A 12V battery containing eight pen cells gives sufficient current (1.8A) to charge the battery connected across the output terminals. The schema also monitors the voltage level of the battery. It automatically cuts off the charging process when its output terminal voltage increases above the predetermined voltage level.

Parts:

P1 = 20K
P2 = 20K
R1 = 390R
R2 = 680R
R3 = 39R-1W
R4 = 27K
R5 = 47K
R6 = 3.3K
R7 = 100R-1W
C1 = 4.7uF-25V
C2 = 0.01uF
C3 = 0.001uF
D1 = 5.6V-1W Zener
D2 = 3mm. Red LED
Q1 = SL100

S1 = On/Off Switch
B1 = 1.5vx8 AA Cells in Series
IC1 = NE555 Timer IC

Timer IC NE555 is used to charge and monitor the voltage level in the battery. Control voltage pin 5 of IC1 is provided with a reference voltage of 5.6V by zener diode D1. Threshold pin 6 is supplied with a voltage set by P1 and trigger pin 2 is supplied with a voltage set by P2. When the discharged cellphone battery is connected to the schema, the voltage given to trigger pin 2 of IC1 is below 1/3Vcc and hence the flip-flop in the IC is switched on to take output pin 3 high. When the battery is fully charged, the output terminal voltage increases the voltage at pin 2 of IC1 above the trigger point threshold.
This switches off the flip-flop and the output goes low to terminate the charging process. Threshold pin 6 of IC1 is referenced at 2/3Vcc set by P1. Transistor Q1 is used to enhance the charging current. Value of R3 is critical in providing the required current for charging. With the given value of 39-ohm the charging current is around 180 mA. The schema can be constructed on a small general-purpose PCB.
For calibration of cut-off voltage level, use a variable DC power source. Connect the output terminals of the schema to the variable power supply set at 7V. Adjust P1 in the middle position and slowly adjust P2 until LED (D2) goes off, indicating low output. LED should turn on when the voltage of the variable power supply reduces below 5V. Enclose the schema in a small plastic case and use suitable connector for connecting to the cellphone battery.

Note

This schema was tested with a Motorola make cellphone battery rated at 3.6V, 320 mAH. In place of 5.6V zener, a 3.3V zener diode was used. The charging current measured was about 200mA. The status of LED is shown in the table.

RF Amplifier IC

RF amplifier IC is a type of electronic amplifier used to convert low-power radio frequency signal into a larger signal strength is important, usually for driving a transmitting antenna. This is usually optimized for high-efficiency, high output power (P1dB) of compression, loss of income on the input and output, better benefits, and optimal heat dissipation.

Box Kit Home Theaters

Box Kit Home Theaters | We live in a world where convenience is increasingly growing in demand. For this reason many home theater buyers expect convenience when it comes to the purchase and set up of their home theater systems. It goes without saying that there are all kinds of consumers in the world and even in matters of convenience supply and demand have not emerged to create a one size fits all society. We all want similar things in many ways yet we still want autonomy and selections from which to choose.

The demands of a society that likes the ease of buying prepackaged goods have reached such a point however that packages are common place in everything from prepackaged dinners to prepackaged home theater systems. On one level these types of prepackaged theater systems provide a great deal of convenience to consumers. Among those benefits is the ability to know the cost of the entire system up front. This is actually a small benefit when compared to some of the other benefits that consumers who purchase these systems experience.

Programmable Gain Amplifier Wiring diagram Schematic

Programmable Gain Amplifier Circuit Diagram . The schema uses the DG212 which controlling the gain using resistors. To calculate the different gains SW4 should be closed. Gain error is determined only by the resistor tolerance op amp offset and CMR will limit accuracy of schema .

Programmable Gain Amplifier Circuit Diagram

Click here to download DG212.pdf datasheet.

Monday, September 1, 2014

HiFi Expandor Wiring diagram Schematic with De emphasis

This is the schematic design of HiFi Expandor Circuit with De-emphasis. The schema is based NE570. The NE570 can be used to construct a high performance compandor suitable for use with music. This type of system can be used for noise reduction in tape recorders, transmission systems, bucket brigade delay lines, and digital audio systems. The diagram to be described contain features which improve performance, but are not required for all applications.

HiFi Expandor Circuit Diagram

The expandor to complement the compressor is shown in the above schema. Here an external op amp is used for high slew rate. Both the compressor and expandor have unity gain levels of 0dB. Trim networks are shown for distortion (THD) and DC shift. The distortion trim should be done first, with an input of 0dB at 10kHz. The DC shift should be adjusted for minimum envelope bounce with tone bursts. When applied to consumer tape recorders, the subjective performance of this system is excellent.

MAX5486 Digital Volume Control

A two channel digital volume control circuit using IC MAX5486 is shown here. MAX5486 can be quite a 40K dual digital volume / balance controller that has a pushbutton interface. The IC has a built in bias voltage source that eliminated the need of an external circuit towards the same purpose and thereby by reduces external parts count.

The IC also comes through an LED status indicator driver circuit that seem to be either employed for driving the status indicator LEDs And this indicates the volume level and balance level. The IC might be operated in one a single or dual power supply and is out there in 24 pin TSSOP package. The volume control circuit Depending on MAX5486 might be applied in a lot applications like personal audio systems, hand held audio devices, home theatre systems, car audio systems, computer audio systems etc.

Simple Tracker circuit Wiring diagram

Most of the guys asked about tracking diagram so today Im going to give you a tracking schema diagram.The special thing of this schema is you can get the signals of this schema through a normal radio.This schema can signals 200M to 400M.According to the environment distance can be changed.And another special thing is you can operate this tracker schema with 3V power.Here I have used BC557 and BC 547 transistors.

Note:

# Build this schema on a PCB
# Dont supply over 3V
# Use H antenna to receive signals