all in one for fun circuit

Magic Lights Circuit using Bi-Colour LED This is the magic lights circuit which use bi-colour LED as the output to provide the light. The circuit uses 14 bi-colour (red and green) LEDs having 3 terminals each. Various dancing colour patterns are generated utilizing this circuit considering that each LED can create three various colours. The middle terminal (pin 2) of the LEDs will be the common cathode pin that is grounded. When a positive voltage...

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bassic of resistor

A resistor is a two-terminal electronic component designed to oppose an electric current by producing a voltage drop between its terminals in proportion to the current, that is, in accordance with Ohm's law: V = IR. The resistance R is equal to the voltage drop V across the resistor divided by the current I through the resistor. Resistors are characterized primarily by their resistance and the power they can dissipate. Other characteristics include...

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the understanding of capacitor

A capacitor is a passive electrical component that can store energy in the electric field between a pair of conductors (called "plates"). The process of storing energy in the capacitor is known as "charging", and involves electric charges of equal magnitude, but opposite polarity, building up on each plate. A capacitor's ability to store charge is measured by its capacitance, in units of farads.Capacitors are often used in electric and electronic...

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Simple Battery Charger with LM350

The schematic diagram can be used for charging the 12V lead acid batteries. The circuit is designed as a constant voltage source with a negative temperature coefficient. The transistor Q1 (BD 140) is used as the temperature sensor. The transistor Q2 is used to prevent the battery from discharging through R1 when the mains power is not available. The circuit is designed based on the voltage regulator IC LM350. The output voltage of the charger...

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easy USB Battery Charger for Lithium Ion Battery

This schematic diagram is used for charging lithium ion battery. The power source is from a computer's USB port. With this circuit, you do not need to build power supply circuits for charging your battery. A USB port is a great power source for charging a single cell li-on battery. It is capable of supplying maximum 5.25V and 500 mA. The circuit above is a USB powered single cell li-on battery charger. LM3622 is used as the controller. This special...

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how to NiCad Battery Charger

This simple and low cost battery charger uses a single transistor as a constant current source. The voltage across the pair of 1N4148 diodes biases the base of the BD140 medium power transistor. The base-emitter voltage of the transistor and the forward voltage drop across the diodes are relatively stable. The charging current is approximately 15mA or 45mA with the switch closed. This suits most 1.5V and 9V rechargeable batteries. The transformer...

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sample 6V Gel Cell Charger Circuit

This is the diagram of 6V Gel Cell charger. The circuit is using NE555 timer as oscillator and TPI31T switching transistor. The schematic diagram designed by Tony Van Roon. Parts List: R1 = 22 ohm, 1W R2 = 270 ohm R3 = 220 ohm *R4 = 715 ohm, 1% *R5 = 3.57K, 1% *R6 = 1.40K, 1% *R7 = 1.47K, 1%C1 = 100nF C2 = 100nF D1 = 1N4001 T1 = TIP31A, B, C (or equivalent) U1 = Timer IC NE555V (or equivalent) S1 = Toggle switch, ON-OFF * Resistors...

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another Multi tone alarm schematic diagram

This is a simple and easy to build multi tone alarm circuit that can be used in burglar alarms or sirens. The circuit is based on dual op-amp MC1458 and LM 380. The two op amps inside the MC 1458 are used to produce square and triangular waves.LM 380 is used to amplify the output.The first op amp IC1a is wired as an astable multi vibrator and second op amp IC1b is wired as an integrator, to make the square wave triangle. The two output square...

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Simple fire alarm circuit with IC timer NE555

Here the simple file alarm circuit based timer ID NE555. The works is simple, the lamp give light to the LDR (Light Depending Resistor) as light sensor. When the light from the lamp covered with smoke then the LDR will change its resistance value and then activated the alarm. The thermistor offers a low resistance at high temperature and high resistance at low imperature. This phenomenon is employed here for sensing the fire. The IC1 (NE555) is...

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fire alarm system

The works is similiar from previous circuit. the LDR sending the light from lamp. When light from lamp blocked by smoke, the alarm will be activated. When there is no smoke the light from the bulb will be directly falling on the LDR. The LDR resistance will be low and so the voltage across it (below .6V). The transistor will be OFF and nothing happens. When there is sufficient smoke to mask the light from falling on LDR, the LDR resistance increases...

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Sound Effects Alarm Generator alarm system

This schematic in very simple and easy to made. The IC produces all the sound effects, the output at Pin 3 being amplified by the transistor. A 64 ohm loudspeaker can be substituted in place of the 56 ohm resistor and 8 ohm loudspeaker. The 2 pole 4 way switch controls the sound effects. Position 1 (as drawn) being a Police siren, position 2 is a fire engine sound, 3 is an ambulance and position 4 is a machine gun effect. The IC is manufactured...

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Water Activated Alarm || simple circuit uses timer IC

This simple circuit uses timer IC to generate frequency. Emitter current from transistor BC 109C powered the IC to work, so the transistor work similiar as switch work. Under dry conditions, the transistor will have no bias current and be fully off. As the probes get wet, a small current flows between base and emitter and the transistor switches on. A larger current flows in the collector circuit enabling the 555 osillator to sound. An On/Off switch...

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simple water alarm system

More explanation about water level circuit, please go to this page. Description: This circuit will trigger with any fluid with a resistance under 900K between the maximum separation distance of the probes. Let me explain further. The circuit uses a 4050B CMOS hex buffer working on a 5 volt supp...

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Zone Alarm System schema

This is the circuit of alarm system with 5 independent zones. Suitable for a small office or home environment. It uses just 3 CMOS IC's and features a timed entry / exit zone, 4 immediate zones and a panic button. There are indicators for each zone a "system armed" indicator. Zone 1 is a timed zone which must be used as the entry and exit point of the building. Zones 2 - 5 are immediate zones, which will trigger the alarm with no delay. Some RF...

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Light Detector diagram

This is a circuit diagram of light detector. This circuit can be used as a sensor of automatic lamp switch, thic circuit also can be used for anti theft alarm circuit. Schematic diagram: Use variable resistor R1 to adjust the light threshold at which the circuit triggers. R1's value is chosen to match the photocells resistance at darkness. The circuit uses a CMOS 4001 IC. Gate U1a acts as the trigger, U1b and c form a latch. S1 to reset the circuit....

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gate alarm circuit

Here the simple gate alarm circuit that built based on CMOS IC 4093B. With CMOS IC, this circuit must be work with small universal power supply. IC1a is a fast oscillator, and IC1b a slow oscillator, which are combined through IC1c to emit a high pip-pip-pip warning sound when a gate (or window, etc.) is opened. The circuit is intended not so much to sound like a siren or warning device, but rather to give the impression: "You have been noticed."...

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simple and easy emergency light and alarm circuit

This is a simple and easy emergency light and alarm circuit. This circuit is permanently plugged into a mains socket and NI-CD batteries are trickle-charged. When a power outage occurs, the lamp automatically illuminates. Instead of illuminating a lamp, an alarm sounder can be chosen. When power supply is restored, the lamp or the alarm is switched-off. A switch provides a "latch-up" function, in order to extend lamp or alarm operation even when...

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a touch activated alarm system

This is a touch activated alarm system. Your alarm system will be activated when someone touching the "trigger". You may use this circuit at your home door, your vehicle etc. Parts list: R1 = 100K R2 = 56K R3 = 10M R4 = 220K P1 = 100K D1 = 1N4004 T1 = 2N3904, or equivalent U1 = 555 Timer* C1 = 47μF/16V** C2 = 33μF/16V** Re1 = Relay*** Notes: *The 555 can be a LM, NE, or MC(cmos) type, they're all pin-compatible. **C1/C2's working voltage ought...

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Electronic Chirping Canary Circuits

Well, for those of you who want to make a small project, this alarm may be an option for you. This circuit will generate the canary chirping sound. The chirp sound of a canary is generated by the oscillation process by resistor R1 and capacitor C1. The capacitor, having a capacitance value of 100 uF, is charging through the resistor, having a resistance of 4.7 K ohms. During this stage, R1 is the bias for the transistor making it operate in the...

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bassic how to make motor cicle alarm

This is a very basic motorcycle alarm design circuit which can be used to secure your motorcycle with very low in cost. Design schematic: Circuit Number Five uses a SPCO/SPDT relay - but you actually only require to make use of a SPST relay. In case you are going to make use of the veroboard layout supplied - you will require to make use of the style of relay specified. But you are able to develop the alarm making use of whatever style of relay...

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Electronic Siren Circuit schema

This is the schematic diagram of electronic siren circuit. The sound produced imitates the rise and fall of an American police siren. When very first switched on, the 10uF capacitors is discharged and each transistors are off. When the push button switch is pressed to 10uF capacitor will charge via the 22k resistor. This voltage is applied towards the base of the BC108B which will turn on slowly. When the switch is released the capacitor will...

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