Showing posts with label led. Show all posts
Showing posts with label led. Show all posts

Automotive LED Timing Light

A useful timing strobe can be constructed using high-brightness LEDs and a few common components. Ignition pulses from the number 1 cylinder high-tension lead are used to trigger the circuit via a home-made inductive pickup. Transistors Q1 & Q2 buffer and amplify the pulses from the pickup, which then drive the inputs of three Schmitt-trigger inverters (IC1a, IC1c & IC1f). Each positive pulse at the inverter inputs causes a low pulse at their outputs, forward-biasing D2 and immediately discharging the 6.8nF capacitor. When the capacitor is discharged, the inputs of the second bank of three inverters (IC1b, IC1d & IC1e) see a logic low level, so their outputs go high, driving Q3 into conduction and powering the LED array. After the pulse ends, the IC1a, IC1c & IC1f inverter outputs return high, reverse biasing D2.

Automotive LED timing light circuit schematic

However, it takes some time for the 6.8nF capacitor to charge to the logic high threshold voltage of the inverters’ inputs, effectively stretching the initial pulse width and lighting the LEDs for the required amount of time. The pickup can be salvaged from an old Xenon timing light or made up from a "C" type ferrite or powered iron core large enough to fit around a HT lead. Some experimentation will be required to determine the number of turns required to achieve reliable triggering. About 100 turns of light-gauge wire proved sufficient on the prototype. A cleat is used to close the magnetic path around the lead and is held in place with a large battery clip. Miniature screened microphone cable can be used to connect the pickup to the circuit, to prevent interference from other sources.
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Build a 16 LED Chaser Circuit Diagram

This 16 LED Chaser Circuit Diagram is a double direction flash. Similar to Digital Ping- Pong 1, there is a movement of a lit dot, up and down along the LEDs length.

16 LED Chaser Circuit Diagram

16 LED Chaser Circuit Diagram


When the D16 lit the situation changes and there is a reverse movement. Lit D15-14 ……D16, is lit making circles when the circuit is under power. The IC1 is an unstable flip- flop supplying with stable frequency pulses (the frequency can be changed by TR1, adjusting the velocity of the LEDs up and down).

This frequency supplies the IC3 (which is a 4-Bit UP and DOWN counter) through 2 gates A-B of the IC2. The output counter supplies the IC4 that is the driver of the LEDs. The parts C- D of The IC2, make a R-S flip- flop, that changes situation, when the edge LEDs D1 and D16 lit.

We have an electronic limit for the situation change. In proportion the shape we make with the LEDs, we can have the proportionate optional result, making various effects.

Part List

R1= 100Kohms
R2= 220Kohms
R3= 470 ohms
TR1= 1Mohms
C1= 330nF 100V MKT
D1-16= LED 5mm
IC1= 555
IC2= 7400
IC3= 74193
IC4= 74154
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Flashing LED Battery status Indicator

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 users 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. 

Circuit diagram :
Flashing-LED Battery
Flashing-LED Battery-status Indicator Circuit Diagram

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
Notes :
  • Mean current drawing of the circuit can be reduced further on by raising R1, R7 and R9 values.


Streampowers
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led light running arrows showing the position circuit and explanation



This
is a led light running circuit with a number generated from IC
CD4093, CD4520 and CD4094.This circuit can adjust the speed with
resistors R1.When entering the power supply to the circuit IC1. A nand
gate IC Oscillator generator circuit is connected to the input signal
generator to pin 1 of IC2 and pin 3 of the IC3.When receiving the
signal from IC1 IC2 will serve up the signal from the logic into the
binary.Then sent to the pin 5 and pin 6 of IC1, IC1, which will process
a nand gate.The IC3 is the signal from IC1 to processing and export
of pin 4, 5, 6 and 7.Then entered into the base of the transistor pins
Q1-Q4.Any work on the transistor connected to the LED pin collector
will glow out come.For the format of the 17 LED Lights, arranged as a
form of directional arrows.
source: www.eleccircuit.com
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