Automatic changeover switch using IC LTC4412

The circuit diagram shown here is of a automatic changeover switch using IC LTC4412 from Linear Technologies. This circuit will be used for the automated switchover of a load between a battery and a wall adapter.LTC4412 controls an external P-channel MOSFET to make a close to ideal diode perform for power switch over and load sharing. This makes the LT4412 a perfect replacement for power supply Oring diodes. a good range of MOSFETs will be driven using the IC and this offers of excellent options like reverse battery protection, manual control input, MOSFET gate protection clamp etc.

The diode D1 prevents the reverse flow of current to the wall adapter when there's no mains supplyr. Capacitor C1 is that the output filter capacitor. Pin 4 of the IC is called the status output. When wall adapter input is gift the standing output pin are going to be high and this will be used to enable another auxiliary P-channel MOSFET (not shown within the circuit diagram.

Notes.

• Assemble the circuit on a good quality PCB.
• The wall adapter input can be anything between 3 to 28V DC.
• The battery voltage can be anything between 2.5V to 28V.
• Do not connect loads that consume more than 2A.
• Maximum continuous drain current of Q1 (FDN306P) is 2.5A.
• D1 (1N5819 is a 1A Schottky diode.
• Q1 (FDN306P) is a P-channel MOSFET.

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Telephone line monitor Circuit Diagram

Telephone line monitor Circuit Diagram

This chic little circuit lets you almanac your buzz conversations automatically. The accessory connects to the buzz line, your band recorder's microphone input, and the recorder's alien ascendancy jack. It senses the voltage in the buzz band and begins recording back the band drops to 5 volts or less.

Parts
R1 270K 1/4 W Resistor
R2 1.5K 1/4 W Resistor
R3 68K 1/4 W Resistor
R4 33K 1/4 W Resistor
C1 0.22uF 150 Volt Capacitor
Q1, Q2 2N4954 NPN Transistor
D1 1N645 Diode
MISC Wire, Plugs To Match Jacks On Recorder, Board, Phone Plug

Notes
1. The circuit can be placed anywhere on the phone line, even inside a phone.
2. Some countries or states require you to notify anyone you are talking to that the conversation is being recorded. Most recoders do this with a beep-beep. Also, you may have to get permission from the phone company before you connect anything to their lines.

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Link Telephone Intercom Circuit

Link Telephone Intercom Circuit

The Link dent is simple and efficient, employing aloof two ICs, bisected a dozen transistors, and a scattering of garden array components. It all runs on 12 volts and is calmly assembled. You can accept your own home intercom amid the kitchen, the garage, the rumpus allowance and at your poolside ‘barby’ and all for beneath than $100!

The “Link” intercom has been advised in such a way that you can buy genitalia for it ‘off the shelf’ at aloof about any adapted electronics retail chain. It uses old beating punch handsets and replaces the AC alarm set with a 9 volt DC buzzer. The accomplished ambit runs from a 12 volt adapted DC accumulation and is acceptable for abbreviate appellation array operation (eg: ‘Gel Cell’). It is acceptable for radio acreage canicule and antic contest (providing you can scrounge abundant 4 wire cable) and may acquisition a abode in pre-schools, old folk’s homes, boy scout/girl adviser halls, churches, kids’ timberline houses/fortresses, or maybe alike added austere uses such as baby offices, factories, workshops and abounding added applications.

The “Link” is advised to accredit one alarm at a time aural a baby breadth (about 100 meters from the ‘black box’ is about the max per handset) and is not acceptable for affiliation to the PSTN (public network) as the voltages and currents acclimated by the PSTN are higher, and will accident the simpler 12 volt circuitry, that employs CMOS ICs etc. The Link will run absolutely appropriately off a 12 volt adapted DC accumulation of alone 200mA or so, and this can be a simple affair, such as a DC bung pack, active to a 7812 regulator dent and adapted clarify caps on the output. Add some leds if you want!

Parts
R1 10k
R2 150k
R3 4k7
R4 47k
R5 2k2
R6 4k7 trimpot
R7 390R
R8 10k
R9 100k
R10 100k
R11 22k
R12-R15 2k2
R16 4k7
R17 4k7
C1 0.22uF
C2 47uF
C3 1uF
C4 2,200uF (power filter cap – not shown, but wired across +12volts & 0v- ground points
Q1-Q5 BC547 n.p.n low gain
Q6 BC 549C high gain with a beta of at least 250+
D1-D7 1N4148 or 1N914 small signal diodes
IC1 NE 556 dual timer chip
IC2 CD 4017B decade counter chip
OC1-OC3 4N25 or 4N28 opto couplers
Tx 1k/8R transformer, with 1k centre tapped
B1-B4 9 volt DC buzzers mounted inside phone handsets
Miscellaneous – wire, cable, matrix or prototyping board, solder, case, 15 volt DC 200ma plug pack
power supply, phone sockets, zip ties, 7812 regulator and filter caps etc.

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Standard low-pass Phone Line Filter

Standard low-pass Phone Line Filter

The aloft diagram is a accepted low-pass blast band clarify (L1,C1,L3,C2). L2 and L4 are bare aback we're ambidextrous with the 'Tip' and 'Ring' of a buzz band which may backpack up to 90VAC!.

I acclimated a agnate ambit on 3 phone-lines aback in the aboriginal 80's back I was active Scottsdale BBS and the filters performed fine. Additional advice can be begin in the ARRL Handbook, etc. For the two capacitors, the college the voltage the better, but the 400V types are the easiest to obtain.

Part and Descriptions

L1,L2 = 6.8mH, inductor
L3,L4 = 10mH, inductor
C1 = 0.022uF, 250-600V
C2 = 0.015uF, 250-600V

Via www. BenJammin.Net

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Huawei C2601 Circuit Diagram

Huawei C2601 Circuit Diagram

Baseband, Power Management, RF, RF Parameters, Assembling Description, C2601 Explosion Diagram, Assembling Description, Troubleshooting, No Vibration, No Display of LCD, “Check UIM” is displayed afterwards the buzz is powered on, No Ringtone, No complete is heard afterwards the alarm is set up, Outgoing Alarm Cannot be Initiated, No Charging, The buzz cannot be powered on, Key Failure, No Signal, Weak Signal, Appendix, Unused Pad of the BGA, Networks to the Test Point, Acronyms and Abbreviations, PCB

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3.6 Volt Cell Phone Battery Meter

3.6 Volt Cell Phone Battery Meter

This is a agnate ambit to the aloft and provides a 4 LED bar blueprint advertence the voltage of a accepted 3.6 volt Lithium – Ion recharable corpuscle buzz battery. The advertence voltage is provided by a TL431 programmable voltage antecedent which is set to 3.9 volts area the TL431 connects to the 1K resistor. The lower advertence for the LED at pin 14 is set with the 5K adjustable resistor.

The programmed voltage of the TL431 is formed out with a voltage affiliate (10K 5.6K). The acclimation terminal or alliance of the two resistors is consistently 2.5 volts. So, if we use a 10K resistor from the acclimation terminal to ground, the resistor accepted will be 2.5/10000 = 250uA. This aforementioned accepted flows through the high resistor (5.6K) and produces a voltage bead of .00025 * 5600 = 1.4 volts. So the blow adapted achievement voltage at the cathode of the TL431 will be 2.5 + 1.4, or 3.9 volts.

Working out the LED voltages, there are three 390 ohm resistors in alternation with addition adjustable (5K) resistor at the bottom. Assuming the basal resistor is set to 2K ohms, the absolute attrition is 390+390+390+2000 = 3170 ohms. So, the resistor accepted is the advertence voltage (3.9) disconnected by the absolute resistance, or about 3.9/ (390 + 390 + 390 + 2000) equals 1.23 mA. This gives us about .00123*2000= 2.46 volts for the basal LED, and about .00123*390 = .48 volts for anniversary footfall aloft the bottom. So, the LEDs should ablaze at accomplish of 2.46, 2.94, 3.42, and 3.9. A absolutely answerable corpuscle buzz array is about 4.2 volts. You can acclimatize the 5.6K resistor to set the top voltage college or lower, and acclimatize the lower 5K resistor to set the basal LED for the everyman voltage. But you do charge a 6 to 12 volt or greater array to ability the circuit.

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Ringing Phone Light Flasher

Ringing Phone Light Flasher

This ambit can be acclimated to afterglow a ball or about-face a anxiety back the buzz rings.Using this ambit nuissence of blast arena at night can be avoided.

When the blast rings the band voltage rises to 72 volts.At this time the LED in the opto-coupler glows and the transistor conducts. Due to this the transistor Q1 conducts.This makes the broadcast ON.The amount affiliated to the broadcast whether ball or alarm turns ON.

Notes.

• Assemble the circuit diagram on a good quality PCB or common board.
• Use a 5V DC power supply for powering the circuit.
• The load can be connected through NC1,NC2 & C points of the relay.

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Detector Cell phone circuit diagram

Detector Cell phone circuit diagram

This cellular buzz detector schematic ambit can faculty the attendance of an activated adaptable corpuscle buzz from a ambit of one and-a-half meters. If a RF arresting is detected the ambit will acquaint you application a complete anxiety (beep complete ) and a blinking LED .

In this blazon of ambit (that use aerial abundance 0.9-3Ghz ) you can not use an LC ambit for abundance affability .The ambit uses a 0.22μF deejay capacitor (C3) to according the RF ambit to ensure the adequacy of the ambit to abduction the adaptable buzz arresting .

This cellular buzz detector can ascertain any action of a adaptable buzz : admission or approachable SMS , video manual or articulation manual . The C3 capacitor charge accept leads breadth of 18 mm with 8 mm agreement amid leads to access the adapted abundance . This baby deejay capacitor acts as a baby gigahertz bend antenna to aggregate the RF signals .

The CA3130 operational amplifier IC is acclimated as a accepted to voltage advocate .This cellular buzz detector cyberbanking ambit diagram can be acclimated to verify the attendance of an alive cellular buzz in the activated breadth .

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Cell phone jammer schematic diagram

Cell phone jammer schematic diagram

A admirable diy gsm jammer or adaptable corpuscle buzz jammer schematic diagram for use alone in GSM1900 with abundance from 1930 MHz to 1990 MHz. The GSM1900 adaptable buzz arrangement is acclimated by USA, Canada and best of the countries in South America.

This corpuscle buzz jammer is not applicative for use in Europe, Middle East, nor Asia. The GSM jammer ambit could block adaptable buzz signals which works on GSM1900 band, additionally alleged DCS.

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