LED Voltmeter for car battery by LM324

The circuit, is a comparator, can measure with step of 1Volt, the voltage of battery of car. The clue of voltage become after comparison of voltage of battery, that is applied in the inverting inputs of amplifiers, with voltages of reference that are produced by a Zener D1,the value of which is such so that it present good thermic stability. With the RV1, we regulate the gradation of voltage that we want.


The optical clue become from four Led.
R1=1K2 R6=10K D2-3-4-5=LED
R2-3-4=680R R7-8-9-10=1K IC1=LM324
R5=15K D1=5V6 /0.5W Zener RV1=10K trimmer
Source :: http://users.otenet.gr/~athsam/voltmeter_with_led_for_car_battery.htm

Low Power LED Voltmeter by LM3914

This is a low power voltmeter circuit that can be used with alternative energy systems that run on 12 and 24 volt batteries. The voltmeter is an expanded scale type that indicates small voltage steps over the 10 to 16 volt range for 12 volt batteries and over the 22 to 32 volt range for 24 volt batteries. Power consumption can be as low as 14mw when operated from 12V and 160mw when operated from 24V. It is possible to set the meter to read equal steps across a variety of upper and lower voltages. The meter saves power by operating in a low duty-cycle blinking mode where the LED indicators are only on and consuming power briefly during a repeating 2 second cycle. The circuit may be switched to a high power mode where the active LED stays on at all times.

Different colored LEDs may be used for the voltage level indicators, this allows the battery state to be read in the dark. With the new blue LEDs, it is possible to have a nice looking rainbow of colors using two each of red, amber, yellow, green, and blue LEDs. The circuit will also work with inexpensive and common red LEDs. If the circuit is to be used in sunlight, ultra-bright LEDs should be used, although even those may be hard to read without some kind of sun shield.
Typical uses include the monitoring of portable battery operated systems and indoor wall mounted home power system charge indicators. The cost of the parts for the circuit is around $25.00 (US) and the parts are commonly available, except for the optional blue LEDs. If blue LEDS are used, expect to pay a premium for them, they cost several dollars each, compared to around 15 cents for the other colors. The blue LEDs do look nice in any case.
The circuit may be built with either the CMOS ICM7555 timer or the more common bipolar 555 timer. The 7555 timer will provide much more efficient operation and should be used for systems with small batteries. The volt meter works nicely with the solar charge controller and low voltage disconnect circuits described in the home-brew section of Home Power #60 and #63.
Read more Source Link : http://www.solorb.com/elect/solarcirc/vom/index.html

230V Blinking LED this circuit is blinking circuit.And here I have used common parts so you all can find them easily.Already I have attached this ci

Already I have posted 230V LED circuit diagrams.This circuit is different than those circuits.Because this circuit is blinking circuit.And here I have used common parts so you all can find them easily.Already I have attached this circuit with our doorbell switch then the visitors who visit my place at night can see it well.





Note:-

# When you deal with 230V be careful because it is dangerous
# Fix this circuit in a plastic box

230V Blinking LED this circuit is blinking circuit.And here I have used common parts so you all can find them easily.Already I have attached this ci

Already I have posted 230V LED circuit diagrams.This circuit is different than those circuits.Because this circuit is blinking circuit.And here I have used common parts so you all can find them easily.Already I have attached this circuit with our doorbell switch then the visitors who visit my place at night can see it well.





Note:-

# When you deal with 230V be careful because it is dangerous
# Fix this circuit in a plastic box

120V AC powered LED Lots of you asked about a circuit which can light up a LED with129V AC current.So this is it.This circuit can light up a Led.If Y

Lots of you asked about a circuit which can light up a LED with129V AC current.So this is it.This circuit can light up a Led.If You want to light up two LEDs I have design a circuit for it.Actually you can attach This circuit for your door bell To see it for the people in the dark.And also you can use this as an AC power Indicator.

AC 120 LED Night Lamp This circuit is 120V LED night lamp.You can use this circuit as an indicator too.When you use the W of those parts be careful.I

This circuit is 120V LED night lamp.You can use this circuit as an indicator too.When you use the W of those parts be careful.If not circuit will burn.



Note

# Build this circuit on a PCB

# Be careful.This circuit operates with AC

Flashing-LED Battery-status Indicator circuit with explanation

Signals when an on-circuit battery is exhausted

5V to 12V operating voltage

A Battery-status Indicator circuit can be useful, mainly to monitor portable Test-gear instruments and similar devices.
LED D1 flashes to attire the user’s attention, signaling that the circuit is running, so it will not be left on by mistake. The circuit generates about two LED flashes per second, but the mean current drawing will be about 200µA.
Transistors Q1 and Q2 are wired as an uncommon complementary astable multivibrator: both are off 99% of the time, saturating only when the LED illuminates, thus contributing to keep very low current consumption.

The circuit will work with battery supply voltages in the 5 – 12V range and the LED flashing can be stopped at the desired battery voltage (comprised in the 4.8 – 9V value) by adjusting Trimmer R4. This range can be modified by changing R3 and/or R4 value slightly.
When the battery voltage approaches the exhausting value, the LED flashing frequency will fall suddenly to alert the user. Obviously, when the battery voltage has fallen below this value, the LED will remain permanently off.
To keep stable the exhausting voltage value, diode D1 was added to compensate Q1 Base-Emitter junction changes in temperature. The use of a Schottky-barrier device (e.g. BAT46, 1N5819 and the like) for D1 is mandatory: the circuit will not work if a common silicon diode like the 1N4148 is used in its place.

Parts:
R1,R7__________220R 1/4W Resistors
R2_____________120K 1/4W Resistor
R3_______________5K6 1/4W Resistor
R4_______________5K 1/2W Trimmer Cermet or Carbon
R5______________33K 1/4W Resistor
R6_____________680K 1/4W Resistor
R8_____________100K 1/4W Resistor
R9_____________180R 1/4W Resistor
C1,C2____________4µ7 25V Electrolytic Capacitors
D1____________BAT46 100V 150mA Schottky-barrier Diode
D2______________LED Red 5mm.
Q1____________BC547 45V 100mA NPN Transistor
Q2____________BC557 45V 100mA PNP Transistor
B1_______________5V to 12V Battery supply

Read more Source: http://www.redcircuits.com/Page135.htm

Lamp Flasher Portable circuit

Here is a portable, high-power incandescent electric lamp flasher. It is basically a dual flasher (alternating blinker) that can handle two separate 230V AC loads (bulbs L1 and L2). The circuit is fully transistorised and battery-powered. The free-running oscillator circuit is realised using two low-power, low-noise transistors T1 and T2. One of the two transistors is always conducting, while the other is blocking.

Due to regular charging and discharging of capacitors C1 and C2, the two transistors alternate between conduction and non-conduction states. The collector of transistor T1 is connected to the base of driver transistor T4 through current-limiting resistor R5. Similarly, the collector of transistor T2 is connected to the base of driver transistor T3 through limiting resistor R6. These transistors are used to trigger Triac1 and Triac2 (each BT136) through optotriacs IC1 and IC2, respectively, and switch on the power supply to external loads L1 and L2.
IC1 and IC2 operate alternatively at a low frequency determined by the values of capacitors C1 and C2. The oscillator circuit built around transistors T1 and T2 generates low frequencies. When transistor T3 conducts, IC1 is enabled to ire Triac1 and bulb L1 glows. Similarly, when transistor T4 conducts, IC2 is enabled to ire Triac2 and bulb L2 glows. Connect the power supply line (L) of mains to bulbs L1 and L2, and neutral (N) to T1 terminals of Triac1 and Triac2.
You can also connect neutral (N) line of the external 230V mains supply to both loads (bulbs L1 and L2) as a common line and then route supply line (L) to respective loads (bulbs L1 and L2). The circuit works off only 3 volts. Since current consumption is fairly low, two AA-type cells are suficient to power the circuit. Assemble the circuit on a general-purpose PCB and enclose in a suitable plastic cabinet with integrated AA-size pen-light cell holder. Drill holes for mounting the ‘on’/‘off’ switch and power switching terminals. Also connect two bulb holders for bulbs L1 and L2.
EFY note:
* While assembling, testing or repairing, take care to avoid the lethal electric shock.
Author: EFY Mag
Read more:http://www.extremecircuits.net/2010/05/portable-lamp-flasher.html

Led light bar scan back and forth led two color circuit with explanation

This circuit is a circuit run on alternating two colors.It uses the 2-color LED with a built-in 3-pin single.This will chase away the glow of each LED until the end.It turns alternating to another color.In any way to the moon on the moon first end, then the LED end of the first LED.Circuit consists of, nand gate ic.Two 10 Counter circuits IC, and IC JK flip flop.
Operation of the circuit is divided into 3 sets.It is a set of signal generators, a set of display and control.Set the signal generator is IC1a,and IC1b number 4011 is a signal generator.The R2, R3, C2 determine the frequency generated.The signal is fed to a set of impressions is the number 4011 IC2 and IC3.The 10 counter circuits to output to the LED, and Is the same, but the work must be performed one at side. Therefore, the signal from pin 11 of IC 2 and tested for D2 and D3,To pin 3 of IC4.The integrated circuit IC 4 is a JK flip flop is connected to a T flip flop.The signal input pin 3 and pin 1 is the output signal.Which sends a signal to the Reset IC either stop working.IC4 on the anniversary, it will output the first time, in contrast to pin1.IC3 make work, IC2 stopped.
IC2 is controlled by signals from pin 1 of IC4, to IC1c.Prior to control IC2.The IC3 is connected to pins 1 through D1 to the control again.

lm3914 led light based music circuit

This is a simple light running circuit by music This circuit is not difficult, is MONO, with a few accessories. Can be connected to the output of a CD or cassette player Time.
Operation of the circuit. Begins to be input via VR. The VR will function fine, signal strength coming. D1 will take disconnected hemisphere plus leaving only the signal hemisphere removed to activation of Q1. Signal is extended through Q1 to pin 5 input of IC1. By C1 forward delay of the IC is not the LED (connected to the output. of IC1) off immediately. The IC IC1 is finished. The act shows the effect of the voltage at IC1 pin 5 of the display by the LED to pins 1-19 of the IC, which is within range. compared to a multiple voltage standard circuits. The circuit can operate effectively. In the R1 that it will determine the current flowing through the LED. To prevent LED damage.
Use should be connected to the input of the circuit. To the speaker terminals, change the value of R3 is 10k and IC1 can choose to display two types Bar (Bar) when the pin 9 and a power source. Dots (Dot) on 9-pin to float to drop.

Source : led light based music circuit using lm3914

1.5 Volt LED Flashers The LED flasher circuits below operate on a single 1.5 volt battery

The LED flasher circuits below operate on a single 1.5 volt battery. The circuit on the upper right uses the popular LM3909 LED flasher IC and requires only a timing capacitor and LED.

The top left circuit, designed by Andre De-Guerin illustrates using a 100uF capacitor to double the battery voltage to obtain 3 volts for the LED. Two sections of a 74HC04 hex inverter are used as a squarewave oscillator that establishes the flash rate while a third section is used as a buffer that charges the capacitor in series with a 470 ohm resistor while the buffer output is at +1.5 volts. When the buffer output switches to ground (zero volts) the charged capacitor is placed in series with the LED and the battery which supplies enough voltage to illuminate the LED. The LED current is approximately 3 mA, so a high brightness LED is recommended.

In the other two circuits, the same voltage doubling principle is used with the addition of a transistor to allow the capacitor to discharge faster and supply a greater current (about 40 mA peak). A larger capacitor (1000uF) in series with a 33 ohm resistor would increase the flash duration to about 50mS. The discrete 3 transistor circuit at the lower right would need a resistor (about 5K) in series with the 1uF capacitor to widen the pulse width.

AC Line powered LEDs The circuit below illustrates powering a LED (or two) from the 120 volt AC line using a capacitor to drop the voltage and a smal

The circuit below illustrates powering a LED (or two) from the 120 volt AC line using a capacitor to drop the voltage and a small resistor to limit the inrush current. Since the capacitor must pass current in both directions, a small diode is connected in parallel with the LED to provide a path for the negative half cycle and also to limit the reverse voltage across the LED. A second LED with the polarity reversed may be subsituted for the diode, or a tri-color LED could be used which would appear orange with alternating current. The circuit is fairly efficient and draws only about a half watt from the line. The resistor value (1K / half watt) was chosen to limit the worst case inrush current to about 150 mA which will drop to less than 30 mA in a millisecond as the capacitor charges. This appears to be a safe value, I have switched the circuit on and off many times without damage to the LED. The 0.47 uF capacitor has a reactance of 5600 ohms at 60 cycles so the LED current is about 20 mA half wave, or 10 mA average. A larger capacitor will increase the current and a smaller one will reduce it. The capacitor must be a non-polarized type with a voltage rating of 200 volts or more.

The lower circuit is an example of obtaining a low regulated voltage from the AC line. The zener diode serves as a regulator and also provides a path for the negative half cycle current when it conducts in the forward direction. In this example the output voltage is about 5 volts and will provide over 30 milliamps with about 300 millivolts of ripple. Use caution when operating any circuits connected directly to the AC line.

AC Line powered LEDs The circuit below illustrates powering a LED (or two) from the 120 volt AC line using a capacitor to drop the voltage and a smal

The circuit below illustrates powering a LED (or two) from the 120 volt AC line using a capacitor to drop the voltage and a small resistor to limit the inrush current. Since the capacitor must pass current in both directions, a small diode is connected in parallel with the LED to provide a path for the negative half cycle and also to limit the reverse voltage across the LED. A second LED with the polarity reversed may be subsituted for the diode, or a tri-color LED could be used which would appear orange with alternating current. The circuit is fairly efficient and draws only about a half watt from the line. The resistor value (1K / half watt) was chosen to limit the worst case inrush current to about 150 mA which will drop to less than 30 mA in a millisecond as the capacitor charges. This appears to be a safe value, I have switched the circuit on and off many times without damage to the LED. The 0.47 uF capacitor has a reactance of 5600 ohms at 60 cycles so the LED current is about 20 mA half wave, or 10 mA average. A larger capacitor will increase the current and a smaller one will reduce it. The capacitor must be a non-polarized type with a voltage rating of 200 volts or more.

The lower circuit is an example of obtaining a low regulated voltage from the AC line. The zener diode serves as a regulator and also provides a path for the negative half cycle current when it conducts in the forward direction. In this example the output voltage is about 5 volts and will provide over 30 milliamps with about 300 millivolts of ripple. Use caution when operating any circuits connected directly to the AC line.

1.5 Volt LED Flashers The LED flasher circuits below operate on a single 1.5 volt battery

The LED flasher circuits below operate on a single 1.5 volt battery. The circuit on the upper right uses the popular LM3909 LED flasher IC and requires only a timing capacitor and LED.

The top left circuit, designed by Andre De-Guerin illustrates using a 100uF capacitor to double the battery voltage to obtain 3 volts for the LED. Two sections of a 74HC04 hex inverter are used as a squarewave oscillator that establishes the flash rate while a third section is used as a buffer that charges the capacitor in series with a 470 ohm resistor while the buffer output is at +1.5 volts. When the buffer output switches to ground (zero volts) the charged capacitor is placed in series with the LED and the battery which supplies enough voltage to illuminate the LED. The LED current is approximately 3 mA, so a high brightness LED is recommended.

In the other two circuits, the same voltage doubling principle is used with the addition of a transistor to allow the capacitor to discharge faster and supply a greater current (about 40 mA peak). A larger capacitor (1000uF) in series with a 33 ohm resistor would increase the flash duration to about 50mS. The discrete 3 transistor circuit at the lower right would need a resistor (about 5K) in series with the 1uF capacitor to widen the pulse width.

LED Circuit AC Powered compact design

AC Powered LED Circuit

AC Powered LED

The following LED circuit is a compact design using supplied with ac power. LED circuit is very useful as an indicator light on the AC power source voltage 100-240V AC.

LED circuit is quite efficient because it does not need to pay extra for the step-down transformers. However, LED circuits need to be stored in a plastic box for safe to use.

LED circuit is also quite resistant to voltage spikes and surges. As an indicator light should use bright LED colors, like blue and white.

AC Powered LED Circuit

Blown Fuse indicator LED Display

A Fuse be the equipment protects that use often most. Because of cheapness can use protect electronics expensive circuit. Generally when fuse torn us can know immediately. but in sometimes Fuse torn already we don’t know. such as in electricity automobile system brake system , the system delays the electric current very much, etc. Fuse torn get into trouble at we must know for immediately the safety. I then beg for to advise the circuit is simple. It is can show with , LED that now. Fuse torn already please. See the illustration by equipment value that show that note for Voltage Source 12V , but if friends want to apply to the level Volt the other. As a result change value R1 and R2 get by can calculate from R1 = (Vin – 2) x 50 and R2 = (Vin – 2) x 10000/2 . Think the work of the circuit has a little, It may help to give friends comfortably go up please sir.

Solar Power walkway marker Led display

These are the little lights with the stake on the bottom that you can push into the ground along your driveway or sidewalk and have the solar panel on top. The solar cell charges a AA NiCd battery during the day and at night the battery powers the LED. The circuit board in this particular model was originally designed to hold a pair of 5mm amber LEDs, but the manufacturer apparently found a source of higher power 10mm amber LEDs and the final product only needs one of these. Due to the limited space, many of the components are surface mount. The transistors are both 2N3904 equivalent surface mounts. Unfortunately, the capacitor is also surface mount and is unmarked.

The charging circuit is fairly simple and has a photovoltaic solar cell to charge the battery and a diode to prevent the battery from powering the cell when it’s dark. Now moving along, there is a cadmium sulphide (CdS) photo resistor, a 10k resistor and a 1k resistor that forms a voltage divider at the base of Q1. When light hits the photo resistor, it has a low resistance which is amplified by the transistor. The collector is tied to the base of the left hand transistor, so when it’s on it clamps its base to ground and prevents it from oscillating. When it’s dark and the CdS Cell has a high resistance, the right transistor is off which allows the rest of the circuit to begin oscillating.

Read More Source:

http://silenceisdefeat.org/~lgtngstk/Sites/tls.html

Thank you.

Inductor An inductor is a loop of wire that stores energy in the form of a magnetic field. It has uses in oscillators, filters, voltage sources and co

Inductor

An inductor is a loop of wire that stores energy in the form of a magnetic field. It has uses in oscillators, filters, voltage sources and converters.

Theory checklist:

• Inductive Reactance
• Back EMF
• Q factor

Modes of operation:

• LC filters and the tank circuit
• Autotransformer
• Transformer

LED 12V Lead Acid Battery Meter with LM339

In the circuit below, a quad voltage comparator (LM339) is used as a simple bar graph meter to indicate the charge condition of a 12 volt, lead acid battery. A 5 volt reference voltage is connected to each of the (+) inputs of the four comparators and the (-) inputs are connected to successive points along a voltage divider. The LEDs will illuminate when the voltage at the negative (-) input exceeds the reference voltage. Calibration can be done by adjusting the 2K potentiometer so that all four LEDs illuminate when the battery voltage is 12.7 volts, indicating full charge with no load on the battery. At 11.7 volts, the LEDs should be off indicating a dead battery. Each LED represents an approximate 25% change in charge condition or 300 millivolts, so that 3 LEDs indicate 75%, 2 LEDs indicate 50%, etc. The actual voltages will depend on temperature conditions and battery type, wet cell, gel cell etc.

Source : http://ourworld.compuserve.com/homepages/Bill_Bowden/

Mains Operated LED Circuit Diagram and explanation

Small in size! Big in use

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Here is a simple and powerful LED circuit that can be operated directly from the AC 100 volt to AC 230 Volts mains supply. The circuit can be used as mains power locator or night lamp etc.. The resistor R1,R2 and capacitor C1 provides necessary current limiting. The circuit is sufficiently immune against voltage spikes and surges.

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Circuit's pictures:

Front View of 220 Volt AC Operated LED Circuit

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Circuit diagram:

Mains Operated LED Circuit Diagram

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Parts:

D1 = 1N4007
D2 = 1N4007
D3 = 1N4007
D4 = 1N4007
R2 = 1M-1/2W
R1 = 470R-1/2W
C1 = 220nF-275vAC
D5 = 5mm. Blue LED

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Features:

1. Small in size!
2. Blue LED operated on mains voltage
3. Suited for mains indicator or other pilot lamps
4. For safety guidance, stairs, corridors…
5. Special X2 safety capacitor
6. 100Vac to 240Vac 50Hz or 60Hz Operated
7. Dimensions: 28x18mm / 1.10 x 0.71"

Note:

• Only for use inside a cabinet
• The capacitor C1 can be polyester type.
• Also white LED can be used in this circuit.
• Assemble the circuit on a general purpose PCB.

Safety and Hazard WARNINGS:

This circuit operates on a lethal power voltage. Mount the circuit in a protective cabinet prio to applying AC Power. Do not modify the circuit - Wait 10 minutes before touching the circuit after disconnecting the AC Power. This circuit is not intended for children.

via: http://www.extremecircuits.net/2010/08/mainsfuse-failure-indicator.html