L200 VOLTAGE REGULATOR SOFT START MECHANISM ELECTRONIC DIAGRAM

L200 VOLTAGE REGULATOR SOFT START MECHANISM ELECTRONIC DIAGRAM

The Vo follows the voltage at pin 2 at less than 0.45 V since a voltage of more than 0.45 V cannot be produced between pins 5 and pins 2.

Constant current ic is charge capacitor C, where

ic= Vsc/R

After the time ton, the output reaches it’s nominal value

Vo-Vsc = (Ic.ton)/C

ton=C.[(Vo-0.45)/0.45].R = CVoR/0.45

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12 V Bidirectional Motor Control Circuit

This simple circuit drives DC motors with a maximum current of 1 A and can be built with readily available components.The output voltage is adjustable between 0 and 14 V and the polarity can be changed so that not only motor speed but also rotation direction can be adjusted by turning a knob.

The circuit is also ideal as a controller for a DC model railway or small low voltage hobby tool. Power for the circuit is supplied by a 18 V mains transformer rated at 1.5 A. Diodes D1to D4 rectify the supply and capacitor C1 provides smoothing to give a DC output voltage of around 24 V. A classic ‘H’ bridge configuration is made up with transistors T1/T3 and T2/T4. Transistors T5 and T6 together with resistors R7 and R8 provide the current sense and limiting mechanism. The maximum output current limit can be changed from 1 A by using different value resistors for R7 and R8: IOUT = 0.6 V / R where R gives the value for R7 and R8. For increased current limit the mains transformer and diodes will need to be changed to cope with the extra current as well as the four transistors used in the bridge configuration.

Circuit diagram:

  12 V Bidirectional Motor Control Circuit Diagram

Motor speed control and direction is controlled by a twin-ganged linear pot (P1). The two tracks of P1 together with R1/R2 and R3/R4 form two adjustable potential divider networks. Wiring to the track ends are reversed so that as the pot is turned the output voltage of one potential divider increases while the other decreases and vice versa.

In the midway position both dividers are at the same voltage so there is no potential difference and the motor is stationary. As the pot is rotated the potential difference across the motor increases and it runs faster. The voltage drop across D5 and D6 is equal to the forward voltage drop VBE of the bridge transistors and ensures that the motor does not oscillate in the off position with the pot at its mid point.

Author :Christian Tavernier

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Pills Reminder

4 - 6 - 8 - 12 - 24 - 48 hours setting LED or Beep Alert - 9V Battery Supply

Circuit purpose:

A Pills Reminder is a device that operates a flashing LED (and/or a beeper) at a fixed hour interval. A choice of time-intervals as wide as possible is available with this circuit, namely 4, 6, 8, 12, 24 and 48 hours.

Operation Mode:

At first you must choose the hour interval by switching SW1 to the desired value, then apply power by means of SW2.
After the hour delay chosen has elapsed the LED will start flashing at 2Hz, i.e. two times per second. This status will last until pushbutton P1 is pressed: then the LED will turn off, but the circuit will continue its counting and the LED will flash again when the same hour interval as before is reached.

A noteworthy feature of this circuit, usually not found in similar devices, is that the internal counter is not reset when P1 is pressed: this allows a better time-interval precision.Let us explain this feature with an example: suppose you have set the time interval to 24 hours and started the Pills Reminder at 8 oclock. Next day, at 8 oclock the LED will start flashing, but you, for some reason, notice the flashes at 8:10 and press P1 to stop the LED. With most devices of this kind, the counter will be reset, causing the LED to start flashing next day at 8:10 oclock.
This will not happen with this circuit and the LED will start flashing next day always precisely at 8 oclock even if you pressed P1 at 9 or 10 oclock.

Circuit diagram:

Pills Reminder Circuit Diagram

Parts:

R1______________10M  1/4W Resistor
R2,R3,R4_______100K  1/4W Resistors
R5,R7___________10K  1/4W Resistors
R6_______________1K  1/4W Resistor
C1,C2___________22pF  63V Ceramic Capacitors (See Notes)
C3______________22µF  25V Electrolytic Capacitor
C4,C5__________100nF  63V Polyester Capacitors
C6_______________1µF  63V Polyester, Multilayer Ceramic or Electrolytic Capacitor
IC1____________4060  14 stage ripple counter and oscillator CMos IC
IC2____________4040  12 stage ripple counter CMos IC
IC3____________4082  Dual 4 input AND gate CMos IC
IC4____________4075  Triple 3 input OR gate CMos IC
IC5____________4520  Dual binary up-counter CMos IC
IC6____________4001  Quad 2 input NOR Gate CMos IC
D1_____________5 or 10mm red LED
XTAL_________32.768  kHz Sub-miniature Watch crystal
P1_____________SPST  Pushbutton
SW1____________2 poles 6 ways Rotary Switch
SW2____________SPST  Toggle or Slide Switch
B1_______________9V  PP3 Battery
Clip for PP3 Battery

Alternative Clock Parts:

R8_______________1K  1/4W Resistor
R9_____________330K  1/4W Resistor
R10_____________20K  1/2W Cermet or Carbon Trimmer
R11______________1K  1/2W Cermet or Carbon Trimmer
C7_______________1µF  63V Polyester Capacitor
IC7____________7555 or TS555CN CMos Timer IC

Circuit Operation:

The clock of the circuit is made of a stable oscillator built around two inverters embedded into IC1 and a Watch crystal oscillating at 32.768kHz. This frequency is divided by 16384 by the internal flip-flop chain of IC1 and a 2Hz very stable clock frequency is available at pin #3 of this IC.

IC2 counter and IC3A 4 input AND gate are wired in order to divide by 3600 the 2Hz clock, therefore, a pulse every 30 minutes is available at the clock input of IC5.

The division factor of this IC is controlled by IC3B and the position of SW1A and B, selecting from six time-intervals fixed to 4, 6, 8, 12, 24 and 48 hours.

The set-reset flip-flop formed by IC6B and IC6C is set through IC4C each time a low to high transition is present at the pin of IC5 selected by SW1B cursor. IC6A and C4 provide to set the flip-flop also when a high to low transition is present at SW1B cursor.

When the flip-flop is set, IC6D is enabled and the 2Hz frequency available at pin #3 of IC1 is applied to pin #13 of IC6D causing the flashing LED operation. The flip-flop can then be reset by means of P1.

A master reset is automatically done at switch on by means of C6 and R7.

Alternative Clock:

Sometimes, the Watch crystal can be difficult to locate, or could be considered too expensive. For those willing to avoid the use of a Watch crystal and to accept less time accuracy, an alternative clock generator circuit is provided, directly oscillating at 2Hz, thus avoiding the use of divider ICs.

A CMos 7555 Timer IC generates a stable 2Hz square wave, whose frequency must be accurately set by means of two trimmers. R10 must be adjusted first for coarse tuning, then R11 for fine tuning.

Setting precisely the 2Hz frequency of this oscillator is a rather difficult task, and can be done with great patience and the aid of a clock, a chronometer or, best, a digital frequency meter capable of measuring very low frequencies.

In any case, after an accurate setup, this oscillator showed a very stable performance, not affected by battery voltage variations and an accuracy of about ±30 seconds per 24 hours interval.

Notes:

• 
  
  Wanting the utmost time precision and if a digital frequency meter is available, a 5-50pF 50V Ceramic Trimmer Capacitor can be used in place of C2. It must be adjusted in order to read exactly 32.768kHz on the meter display with the input probe connected to pin #9 of IC1.
• 
  
  A Piezo sounder (incorporating a 3KHz oscillator) can be added to provide a visual plus audible alert. It must be wired across pin #11 of IC6D and negative ground, respecting polarities. Remove D1 and R6 if the visual alert is not needed.

Source : www.redcircuits.com

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Broken Charger Connection Alarm

Detects if a device is not properly connected to its supply Suitable for battery chargers, portable appliance supplies etc.

The above circuit can be useful to detect if the load of any battery charger or plug-in adapter supply is not properly connected. The load can be a set of batteries to be charged or any other type of battery or low dc voltage operated device. The circuit can safely operate over a 3 to 15V range and 1A max. Current, provided the supply voltage is about one volt higher than the voltage required by the load.

The circuit is inserted between the supply and the load; therefore, until a trickle-charging current of at least 100µA is flowing towards the load, D1 and D2 will conduct. The forward voltage drop (about 1V) available across the Diodes drives Q2 into conduction and, consequently, Q1 will be cut-off. If no appreciable load is connected across the circuits output, Q2 will become cut-off, Q1 will conduct and the Piezo-sounder will beep.

Circuit diagram:

Broken Charger Connection Alarm Circuit Diagram

Parts	Description
R1	10K
R2	1K
R3	1K
Q1	BC557
Q2	BC557
D1	1N4007
D2	1N4007
D3	Red LED
BZ1	Piezo Sounder

Notes:

• An optional LED and its series limiting resistor can be wired in parallel to BZ1, as shown in dotted lines in the circuit diagram.
• In this case you may omit the Piezo-sounder in order to obtain a visual alert only.

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1994 Lumina APV Van Wiring Diagram

1994 Lumina APV Van Wiring Diagram

The Part of 1994 Lumina APV Van Wiring Diagram: camshaft position sensor, hall effect, sensor ground,

amplifier, instrument cluster, red wire, bypass switch, control reference, ignition module control, electronic ignition module, powertrain control module, spark reference input

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I O Experimenter Board PCB Version

If you are tired of connecting the same I/O devices every time you prototype a new project then this board could save you a lot of time. All the necessary pins of the devices on the board are accessible through headers that allows easy connection of the board to a breadboard circuit or other development boards (Arduino, etc) using jumper wires.

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LV8741V PWM Stepping Motor

Using the LV8741V PWM stepping motor driver IC can be designed a very simple and efficiency DC motor driver electronic project . As you can see in the circuit diagram , this electronic project require few external electronic parts . The maximum output current that can be provided by this PWM current-control stepping motor driver IC is up to 1.5 ampere . The reference voltage is set by the voltage applied to the VREF pin and the two inputs ATT1 and ATT2.

LV8741V PWM Stepping Motor Circuit Diagram

When the output current is below the output short-circuit protection current, the output is controlled by the input signal. The setting conditions for the above PWM current-control DC motor driver circuit diagram are as follows : Auto recovery-type output short-circuit protection function (EMM = Low), Output enable function fixed to output ON state (OE = High), Current limit reference voltage setting = 100% (ATT1 = Low, ATT2 = Low) ,Chopping frequency : 37kHz (RCHOP = 43k ).

Voltages required by this LV8741V current-control DC motor driver are from 9.5 to 35 volt for motor power and from 2.7 to 5.5 for logic power supply .

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Headphone Amplifier with IR Communication

This low cost project can be used to reproduce an audio from TV without creating any disturbance from other people. No wire will be used by the circuit between the TV and the headphone because instead of using wires, it utilizes the invisible infrared light for the transmission of audio signals from the TV going to the headphone. The range that can be covered can reach up to 6 meters without using any lens but if required, the range can be made to extend with the use of lenses and reflectors with transmitters and receivers that comprise the IR sensors.

Headphone Amplifier with IR Communication Circuit diagram

Two series connected IR LEDS are being driven by the two-stage transmitter amplifier that uses the IR transmitter. The audio output from TV to the IR transmitter is coupled by using an audio output transformer that is reversely connected. The audio signals are amplified by the transistors BC547 & BD140. These audio signals are received from TV through the low output impedance windings for TV connection of the audio transformer while high impedance for IR transmitter connection.

A 9V source can power the IR transmitter with the LED functioning as power-on indicator.

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Battery Charger Using LTC4078

Using the LTC4078 standalone linear charger circuit you can design a very simple single-cell battery charger circuit for Li-Ion Li-Polymer battery . This LTC4078 battery charger circuit works from both wall adapter and USB inputs. This charger can detect power at the inputs and automatically select the appropriate power source for charging.

Battery Charger Using LTC4078 Circuit diagram

As you can see in the circuit diagram , this Li-Ion Li-Polymer charger requires few external components and you will need to apply just few equations ,to design a full work USB , wall adapter charger .
The charge current can be programmed up to 950mA from wall adapter input . IUSB pin is used for program the charge current for USB power that can be programmed by connecting a resistor to the ground.

The voltage on this pin can be used to measure the battery current delivered from the USB input using the following formula: IBAT = (VIUSB/RIUSB)*1000 . ITERM pin is the termination current threshold program that is set by connecting a resistor to ground. ITERMINATE is set by the following formula:
ITERMINATE =100V/RITERM ; RITERM =100V/ITERMINATE IDC pin is used for program the charge current for wall adapter power that is set by connecting a resistor to ground.The voltage on this pin can be used to measure the battery current delivered from the DC input using the following formula: IBAT = (VIDC/RIDC)*1000 .

The charge current delivered to the battery from the wall adapter or USB supply is programmed using a single resistor from the IDC or IUSB pin to ground and can be calculated using the following equations:
RIDC =1000V/ICHRG-DC , ICHRG-DC = 1000V/RIDC - Wall adapter
RIUSB =1000V/ICHRG-USB , ICHRG-USB =1000V/RIUSB – USB port.

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