Rangkaian Sirine Sederhana 2 Transistor

This is a simple Siren circuit used 2 transistor . The siren circuit produced imitates the rise and fall of an American police siren. When first switched on the 10u capacitors is discharged and both transistors are off. When the push button switch is pressed to 10u capacitor will charge via 22k resistor. This voltage is applied to the base of the BC108B which will turn on slowly. When the switch is released the capacitor will discharge via the 100k and 47k base resistors and the transistor will slowly turn off. The change in voltage alters the frequency of the siren.

Skema rangkaian sirine sederhana

Current drain is fairly high in this circuit so a suitable power supply is required. The duration the tone takes to rise and fall is determined by the 10u and 22k resistor. These values may be varied for different effects.

Transistor 2N3702 description

This device designed for use as PNP general purpose amplifier and switches requiring collector currents to 300mA.



Absolute Maximum Ratings

• Collector-Emitter Voltage (VCEO ): -25 V.
• Collector-Base Voltage (VCBO ): -40 V.
• Emitter-Base Voltage (VEBO ): -5.0 V.
• Collector Current - Continuous (IC): -500 mA.
• Operating and Storage Junction Temperature Range (TJ, TST): -55 ~ +150 C.
• Current Gain (hFE DC ): 60 - 300.

Pin transistor BC 108

• Low current (max. 100 mA).
• Low voltage (max. 45 V).
• Current Gain (hFE DC) : 110 - 450.

Read More

Skema Rangkaian Alarm Kebakaran

Alarm Kebakaran

Skema Rangkaian Alarm Kebakaran

This is a simple fire alarm circuit, which can help the user's color interested against fire accidents based on a LDR and lamp pairs an alarm for sensing the fire.The works by sensing the smoke Produced During fire.The circuit produces an audible alarm the fire breaks Pls out with smoke.

When a number of smoke passes Between a bulb and an LDR, the amount of light falling on the LDR decreases. This Causes the resistance
of the LDR to Increase and the voltage at the base of the transistor is pulled high due to Which the supply to the COB (chip-on-board) is completed. Different cobs are available in the market to generate Different Musical. The choice of the COB depends on the user. The signal generated by COB is amplified by an audio amplifier. In this circuit, the audio power amplifier is wired around TDA2002. The sensitivity of the circuit depends on the distance Between bulb and LDR as well as the setting of preset VR1. Thus by placing the bulb and the LDR at appropriate distances, one May Vary preset VR1 to get optimum sensitivity. An ON / OFF switch is suggested to turn the circuit on and off as Desirable.

Read More

Motorcycle Alarm Circuit Using IC 555

Rangkaian Motorcycle Alarm

Skema Rangkaian IC 555 Motorcycle Alarm

This circuit features an intermittent siren output and automatic reset. It can be operated manually using a key-switch or a hidden switch; but it can also be wired to set itself automatically when you turn-off the ignition. By adding external relays you can immobilize the bike, flash the lights etc. I have used Andy's Asymmetric Timer as the basis for this design.

Any number of normally-open switches may be used. Fit "tilt" switches that close when the steering is moved or when the bike is lifted off its side-stand or pushed forward off its centre-stand. Use micro-switches
GFto protect removable panels and the lids of panniers etc.
The alarm's standby current is virtually zero - so it won't drain your battery. Once activated - the rate at which the siren switches on and off is controlled by R7, R8 & C4. For example, increasing R7 will make the sound period longer - while increasing R8 gives longer silent periods.

The circuit is designed to use an electronic Siren drawing 300 to 400mA. It's not usually a good idea to use the bike's own Horn because it can be easily located and disconnected. However - if you choose to use the Horn - remember that the alarm relay is too small to carry the necessary current. Connect the coil of a suitably rated relay to the "Siren" output. This can then be used to sound the Horn, flash the lights etc.

The circuit board and switches must be protected from the elements. Dampness or condensation will cause malfunction. Connect a 1-amp in-line fuse AS CLOSE AS POSSIBLE to your power source. This is VERY IMPORTANT. The fuse is there to protect the wiring - not the alarm. Exactly how the system is fitted will depend on the make of your particular machine - so I'm unable to provide any further help or advice in this regard.

When you set the alarm - if one of the switches is closed - the siren will sound. This could cause annoyance late at night. A small modification will allow you to Monitor The State Of The Switches using LEDs. When the LEDs are all off - the switches are all open - and it's safe to turn the alarm on


Source: http://www.zen22142.zen

Read More

Water Activated Alarm Circuit

This Water Activated Alarm circuit uses a NE555 timer wired as an astable oscillator and powered by the emitter current of the transistor BC109C. Under dry conditions, the transistor will from have no bias current and be fully off. As the probes get wet, a small current flows Between the base and emitter and the transistor switches on. A larger current flows in the collector circuit enabling the IC NE555 osillator to sound.

Skema Rangkaian Water Activated Alarm

Probe/contacts may use a non-reactive metal. Gold or silver plated contacts from an old relay May be Used, however a cheap alternative is to wire alternate copper strips from a piece of veroboard. These will eventually oxidize over but as very little current is flowing in the base circuit, the higher impedance the caused by oxidization is not Important. No base resistor is Necessary as the transistor is in emitter follower, current limit being the impedance at the emitter (the oscillator circuit).

Circuit from: www.epanorama.net

Read More

Rangkaian Buzzer Elektronik

Gbr. Skema Rangkaian Elektronic buzzer

Simple Electronic buzzer series is a series that only use 2 resistor, 3 capacitor , NE555 Chip, switch, and speaker. string up series of simple electronic buzzer is also very easy and simple. IC NE555 is the frequency of 1 kHz when the switch is pressed. This frequency can be set using the potensiometer 10 KOhm. Picture a series of simple electronic buzzer can be seen above:




IC NE555

555 timer IC provides practical solutions and relatively inexpensive for a variety of electronic applications related to the timing (timing). Especially two of the most popular application is a series of monostable and astable timing.

• Pin 1: Ground, is the input pin of the source of the negative DC voltage
• Pin 2: trigger, negative input from the lower comparators (comparator B) that maintain oscillation capacitor voltage in the lowest 1 / 3 Vcc and set RS flip-flop
• Pin 3: output, the output pin of the IC 555.
• Pin 4: reset, the pin that serves to reset the latch inside the IC to be influential to reset the IC work. This pin is connected to a PNP-type transistor gate, so the transistor will be active if given a logic low. Normally this pin is connected directly to Vcc to prevent reset
• Pin 5: control voltage, this pin serves to regulate the stability of the reference voltage negative input (comparator A). This pin can be left hanging, but to ensure the stability of the reference comparator A, usually associated with a capacitor of about 10nF to berorde pin groun
• Pin 6: threshold, this pin is connected to the positive input (comparator A) which will reset the RS flip-flop when the voltage on the capacitor from exceeding 2 / 3 Vc
• Pin 7: discharge, this pin is connected to an open collector transistor Q1 is connected to ground emitternya. Switching transistor serves to clamp the corresponding node to ground on the timing of certain
• Pin 8: vcc, pin it to receive a DC voltage supply. Usually will work optimally if given a 5-15V. the current supply can be seen in the datasheet, which is about 10-15mA.

Read More