Showing posts with label LED/ Light. Show all posts
Showing posts with label LED/ Light. Show all posts
Thursday, May 5, 2011
19 LED Bar/Dot VU Meter Using LM3915-LM3916 ICs
This 19 LED VU Meter circuit was designed by two monolithic integrated circuits to measure the level of audio signals whose unit of measurement is known as volume unit. The circuit round the IC1 makes input adaptation and amplification with the trimmer TR1 [GAIN]. The circuit round the IC2 makes half-wave rectification of acoustic signal. With switch S1, we select the type of indication, that we will have from the LED. With the prices in resistances R6 and R7 that exists in the circuit, the level of signal, in the entry is 7.8V (gain of first stage IC1, is one), and the difference of level between the LED D10-11, should are 3 db. The positive department of supply, should have the possibility of giving more current, one and it is overloaded with the current of LED.
list componet
R1-2 : 10Kohm C1 : 100uF/25V D1-19 : LED 3 or 5mm any colour. R3-4 : 10Kohm C2-5 : 10uF/25V D20-21: 1N4148 R5-8-9 : 1Kohm C3-4 : 100nF IC1 : TL 072 R6 : 330Kohm C6 : 1uF/25V IC2 : LM3915 R7 : 62Kohm S1 : mini Switch IC3 : LM3916 TR1: 47Kohm Trimmer
This 19 LED Bar/Dot VU Meter circuit from http://users.otenet.gr/~athsam/vu_meter_2.htm
Wednesday, May 4, 2011
10 LED VU Meter Using LM3915 IC
This circuit is a very simple circuit-level indication, with 10 Led. LM3915 IC is used to control the led, as an indicator VU Meter. This circuit uses just one IC and a very few number of external components. It displays the audio level in terms of 10 LEDs. The input voltage can vary from 12V to 20V, but suggested voltage is 12V.
The LM3915 is a monolithic integrated circuit that senses analog voltage levels and drives ten LEDs. The whole display system can operate from a single supply as low as 3V or as high as 25V.
The IC contains an adjustable voltage reference and an accurate ten-step voltage divider. The high-impedance input buffer accepts signals down to ground and up to within 1.5V of the positive supply. Further, it needs no protection against inputs of ±35V. The input buffer drives 10 individual comparators referenced to the precision divider. Accuracy is typically better than 1 dB.
Thursday, March 17, 2011
ON/OFF LED Fade Effect Circuit by Op-Amp LM324
The simple and easy to build on/off LED fade effect circuits included here will specially interest the new electronic hobbyists. Just like the name of the circuit, the light intensity of LEDs in this circuit will fade from high intensity to low intensity and then off.
ON/OFF LED Fade Effect Circuit by Op-Amp LM324 C 30 uF and R 100k (blue color) control the speed of the fading. You can replace the 100K ohm resistor with 100k linear potentiometer so you can adjust the speed any time. You can make the circuit even simplier by leaving out other of the transistors and those leds that are connected to it. Good for power led pulsing etc.
Op-Amp LM324 PinoutLM324 is an OP-Amp amplifier. There 4 op amp, and we just use 2 op amp in above circuit diagram. You may use the other 2 op-amp to build another similar circuit. Transistor is BC547 and the led is ultra bright red with 220 ohm resistor in series.
1.5V LED Flasher Circuit by LM3909
This is a very simple 1.5V LED Flasher circuit based LM3909. It is known that LM3909 is an oscillator, a monolithic one, which is designed to flash Light Emitting Diodes (LED). According to the datasheet, it may deliver pulses of 2 more volts while operating on a supply of 1.5V by using the timing capacitor.
1.5V LED Flasher Circuit by LM3909The LM3909 features low cost, low voltage and low current drain, with a bright-high current LED pulse and wide temperature range. It can be applied on applications such as flashlight finder, siren for toy fire engine, sawtooth generators, emergency locators, warning indicators and etc.
List Component of 1.5V LED Flasher
LED1 : Red LED
C1 : 100uf/16V
IC1 : LM3909
Battery_:_____1.5V AAA
Tuesday, February 22, 2011
LED Pulser Circuit Using Op-Amp LM358
This circuit operates a LED in pulsing mode, LED goes from off state, lights up gradually, then dims gradually. This operation mode is obtained by a triangular wave generator formed by two op-amps contained in a very cheap 8 pin DIL case IC. Transistor Q1 ensures current buffering, in order to obtain a better load drive. R4 & C1 are the timing components: using the values shown in the parts list, the total period is about 4 seconds.
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| LED Pulser Circuit Using Op-Amp LM358 |
- The most satisfying results are obtained adopting for R4 a value ranging from 220K to 4M7. Adopting for R4 a value below 220K, the pulsing effect will be indistinguishable from a normal blinking effect.
- Voltage supply range can be 4 to 6V: 4.5V is the best compromise.
List Component of LED pulser circuit
R1,R2 : 4K7
R3 : 22K
R4 : 2M2 1/4W (See Notes)
R5 : 10K
R6 : 47R
C1 : 1µF Polyester Capacitor
D1 : 5mm. Red LED
IC1 : LM358 Dual Op-amp
Q1 : BC337
Monday, February 21, 2011
Simple 220V AC Blinking LED Using Diac
needed a blingking led for a certain signaling. Voltage was 220V. So I decided to make a simple circuit, consisted of a LED diode, two capacitors, two resistors, a diac and a diode.
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| Simple 220V AC Blinking LED Using Diac |
Activity of the circuit is extraordinarily simple. The capacitor charges by the diode and the resistor. When the voltage on the capacitor achieves 30V the diac "releases" the electrical tension and the capacitor empties thorough the diac, LED blinks. Time base is dependent from the capacitor and the resistor, which is in series with diode 1N4007. Capacitor must be at least for 40V.
Thursday, January 20, 2011
Simple Traffic Light Using 4017 Counter
This circuit operates red, kuning and green LEDs in the correct sequence for a single traffic light. The time taken for the complete red - red & amber - green - amber sequence can be varied from about 7s to about 2½ minutes by adjusting the 1M preset. Some amber LEDs emit light that is almost red so you may prefer to use a yellow LED.
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| Simple Traffic Light circuit |
The 555 astable circuit provides clock pulses for the 4017 counter which has ten outputs (Q0 to Q9). Each output becomes high in turn as the clock pulses are received. Appropriate outputs are combined with diodes to supply the amber and green LEDs. The red LED is connected to the ÷10 output which is high for the first 5 counts (Q0-Q4 high), this saves using 5 diodes for red and simplifies the circuit.
List Component of Simple Traffic Light Circuit
- Resistors : 470 ×3, 22k, 100k
- Capacitors : 0.1µF, 1µF 16V radial, 10µF 16V radial
- Diodes : 1N4148 ×6
- LEDs : red, amber (or yellow), green
- 1M preset, horizontal
- 555 timer IC, such as NE555
- 4017 counter IC
- on/off switch
Sunday, January 16, 2011
3 Volt LED Flasher Using 2 Transistor
Applications due to its simplicity and versatility. This Flasher circuit is great for beginners! If you build it, it will flash. And you can easily change the on-time and flash rate.
The two resistors on the base of the PNP set a threshold voltage and when power is applied the capacitor begins charging toward this voltage. When the capacitor voltage is high enough the two transistors begin to conduct. The current flow causes the voltage across the circuit to drop slightly and this drop causes a drop in the threshold voltage. The lower threshold voltage causes even more current and this positive feedback causes the circuit to rapidly turn on. It stays on until the capacitor discharges at which point a reverse process causes the circuit to suddenly switch off.
- Flashing frequency can be varied by changing R1 value in the 1M - 4M7 range.
- This circuit is very efficient when driving a small 3.2V incandescent lamp. In this case omit the LED and R3, connecting the bulb across Q2 Collector and positive supply, further reducing parts counting.
- Maximum current drawing of the bulb type used should not exceed 100mA.
- In order to facilitate oscillation when a bulb is driven, R2 value should be lowered to 82R or 68R.
R1 : 1M 1/4W Resistor R2 : 100R 1/4W Resistor R3 : 22R 1/4W Resistor C1 : 1µF/63V D1 : LED Q1 : 2N3906 PNP Transistor Q2 : 2N3904 NPN Transistor SW1 : SPST Switch B1 : 3V (Two 1.5V AA or AAA battery)
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