Rongge

Telephone line Based Audio Muting and Light-On Circuit . Very often when enjoying music or watching TV at high audio level, we may not be able to hear a telephone ring and thus miss an important incoming phone call. To overcome this situation, the circuit presented here can be used. The circuit would automatically light a bulb on arrival of a telephone ring and simultaneously mute the music system/TV audio for the duration the telephone handset is off-hook. Lighting of the bulb would not only indicate an incoming call but also help in locating the telephone during darkness. . Telephone line Based Audio Muting and Light-On Circuit diagram :   Telephone line Based Audio Muting and Light-On Circuit Diagram  . On arrival of a ring, or when the handset is off-hook, the inbuilt transistor of IC1 (opto-coupler) conducts and capacitor C1 gets charged and, in turn, transistor T1 gets forward biased. As a result, transistor T1 conducts, causing energisation of relays RL1, RL2, and RL3...

Often, for certain low voltage lighting systems; you would like to turn off the lights during the bright light of the day.  Most commercial day/night switches are designed for AC lighting.  This hobby circuit below was designed for a 12v DC system.  But, it could be modified for other voltage as well.  It uses an inexpensive photo-transistor as the light detector.  An n-channel FET is used to switch power to the lights.  A transistor circuit is included to provide some hysteresis.   This keeps the circuit from fluttering the light during the transition from day to night and night to day.  It is recommended that a plastic tube be placed over the transistor to prevent it from being illuminated by the lights it is controlling.  By selecting the appropriate power FET, the circuit could control over 100 watts worth of 12v lighting.   (July 22, 2008) Source: DiscoverCircuits

This is a fun circuit that can be at parties, for example. The four LEDs flash to the beat of the music. The light organ responds using a microphone to sound.T1 amplifies the signal from MIC. The sensitivity can be adjusted by P1. T4 controls the LEDs.  These are preferably LED's with a high light intensity.MIC is a condenser microphone. The circuit can be powered by a 9 V battery.  LED light Organ Circuit Diagram The 4 Budget This circuit costs about € 6.15. Parts List      R1 = 10 k      R2 = 330 K?      R3, R6, R13 = 100 k      R4, R8, R11, R14 = 47 Ω      R5, R9, R12 = 1.5 MΩ      R7, R10 = 47 k      P1 = 220 K?      C1, C2, C3 = 100 nF      C4 = 100 uF      D1-D4 = LED      T1, T2, T3 = BC547B      T4 = BC557B      M...

The circuit of the running light comprises two integrated circuits (ICs), a resistor, a capacitor and seven light-emitting diodes (LEDs), Decade scaler IC2 ensures that the LEDs light sequentially. The rate at which this happens is determined by the clock at pin 14. The clock is generated by IC1, which is arranged as an astable multivibrator. Its frequency is determined by R1-C1. 6-Channel Running Light Circuit Diagram The touch switch, consisting of two small metal disks is optional. When switch S1 is in position ‘off’, the circuit may be actuated by the touch switch. By the way, this enables the circuit to be used as an electronic die (in which case the LEDs have to be numbered from 1 to 6). The running light is powered by a 9 V battery or mains adapter. It draws a current not exceeding 20 mA. Author: L. v/d Heeden Copyright: Elektor Electronics 1998

The drawing below illustrates a multistage light sequencer using descrete parts and no integrated circuits. The idea is not new and I hear a similar circuit was developed about 40 years ago using germanium transistors. The idea is to connect the lights so that as one turns off it causes the next to turn on, and so forth. This is accomplished with a large capacitor between each stage that charges when a stage turns off and supplies base current to the next transistor, thus turning it on. Any number of stages can be used and the drawing below illustrates 3 small Christmas lights running at about 5 volts and 200mA. The circuit may need to be manually started when power is applied. To start it, connect a momentary short across any one of the capacitors and then remove the short. You could use a manual push button to do this.  Detailed operation: Assume the circuit doesn't start when power is applied amd all lights are off and all three capacitors are charged to about 5 volts. We connec...

How to build a 40 LED Bicycle Light Electronic circuit Project? This is a very Simple to build This electronic circuit project of 40 LED bicycle light.  The 555 circuit below is a flashing bicycle light powered with four C,D or AA cells (6 volts). Two sets of 20 LEDs will alternately flash at approximately 4.7 cycles per second using RC values shown (4.7K for R1, 150K for R2 and a 1uF capacitor). Time intervals for the two lamps are about 107 milliseconds (T1, upper LEDs) and 104 milliseconds (T2 lower LEDs). Two transistors are used to provide additional current beyond the 200 mA limit of the 555 timer. Simple 40 LED Bicycle Light Circuit Diagram : A single LED is placed in series with the base of the PNP transistor so that the lower 20 LEDs turn off when the 555 output goes high during the T1 time interval. The high output level of the 555 timer is 1.7 volts less than the supply voltage. Adding the LED increases the forward voltage required for the PNP transistor to about 2.7 vo...

The wiring process of fluorescent tube lamp/light with Ballast,Starter is quite easy and simple. In most cases when we buy a fluorescent light it comes in a complete set with all wire connected. If you want do it yourself , you can buy all the parts individually. And you can complete all connection of the fluorescent light/lamp with the help of this wiring circuit diagram. Main parts of Fluorescent Tube Light:      1.Fluorescent Tube      2.Ballast      3.Starter      4.Holder, wire etc. How Fluorescent Light's works: The starter is like a key of fluorescent light because it is used to light up the tube. When we connect the AC supply voltage to the circuit, then the starter act like short circuited and current flow through those filament (located at the first and second end of the tube light) and the filament generate heat and it ionized the gas ( mercury vapor ) in the fluorescent tube lamp. So the gas beco...

Build a Flashing Light with Twilight Switch Circuit Diagram . Flashing light is very useful in order to indicate any obstruction or working in progress. The project automatic flashing light with twilight switch flash light in dark but during day it automatically turns off itself. The circuit diagram of automatic flashing light with twilight switch is shown below where LDR is used as sensor. In the presence of light LDR offer low resistance and in dark it offers high resistance. When there is absence light, LDR offer high resistances which turn off the transistor T1. Due to this darlington pair made from transistor T2 and T3 is turn on which further glow bulb. The feedback from its output is given to the junction of resistor R2 and LDR as shown in circuit diagram. Due to feedback this circuit works as oscillator which work as flasher. Variable resistor VR1 is used to adjust the sensitivity of LDR. Flashing Light with Twilight Switch Circuit Diagram PARTS LIST Resistors (all ¼-watt, ± 5%...

This circuit indicator light level using operational amplifier , LDR and indiction is by LEDs . There are a variety of LDR , its resistance varies from less than 100 ohms on a cloudy day in more than one megohm in complete darkness. A trimmer 2K was used to adjust the range of comparison. This configuration can also be used to indicate   the reconnoiter .  Indicator light using Windows Comparison Circuit Diagram

This is the 12v Light / Dark Switch Circuit Diagram. Often, for certain low voltage lighting systems; you would like to turn off the lights during the bright light of the day.  Most commercial day/night switches are designed for AC lighting.  This hobby circuit below was designed for a 12v DC system.  But, it could be modified for other voltage as well.  It uses an inexpensive photo-transistor as the light detector.  An n-channel FET is used to switch power to the lights.  A transistor circuit is included to provide some hysteresis.   This keeps the circuit from fluttering the light during the transition from day to night and night to day.  It is recommended that a plastic tube be placed over the transistor to prevent it from being illuminated by the lights it is controlling.  By selecting the appropriate power FET, the circuit could control over 100 watts worth of 12v lighting.   (July 22, 2008) 12v Light / Dark Switch Circuit...