Vacuum Tubes Valves
Musical & effects
Yagi Uda Antennas
Metal Detector Circuits
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Light Sensing Circuits
Voltage Detector Circuits
Air-Gas Detection Circuits
Human Sensing Circuits
RF & Radiation
Optical Sensing Circuits
Free Energy Circuits
AC to DC & DC to DC
Solar Cell Circuits
Micro Power Circuits
Switching Power Supplies
Light Laser LED
Digital to Analog
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Data Bus Circuits
Voltage to Pulse
Current to Voltage
Frequency to Voltage
RF Converter Circuits
Sine to Square Wave
Voltage to Current
voltage to frequency
Period to Voltage
Video Wall circuits
TV Video Circuits
Motor Control Circuits
8051 / 8052
PCB CAD Software
Car bike Circuits
555 Timer Circuits
Remote Control Toy
H Bridge Circuit
Interconnection & Timing
Digital Signal Integrity
Digital & Bipolars
Sensors & Detectors
Regulated Power Supply
4 Band Resistor
5 Band resistor
6 Band resistor
Electronic ship siren
The circuit consists of a multivibrator (Ql & Q2), and a low power output stage Q3. The speaker should have an impedance in the region of 40 to 80 ohms. To use a low impedance speaker, connect an output transformer from the emitter of Q3 to ground. Cl and C2 determine the pitch of the siren and the values specified will provide a tone of about...
This circuit mimics the dual-tone drone sound that"s produced by the unusual wind instrument. Urnjunction transistors Ql and Q2 are connected in similar audio-oscillator circuits. Each of the oscillator frequencies is determined by one of the two resistors selected by one of the pushbutton switches, S4 through Sll. The odd-numbered resistors...
This siren provides a constant audio output, but alternates between two separate tones. The LM13080 is set to oscillate at one basic frequency;
Unijunction transistors Ql and Q2 are both connected as relaxation-type, sawtooth oscillators. Transistor Ql is the low-frequency control oscillator and Q2 is the tone generator. Sawtooth waveforms are produced at the emitter terminals. Without R4 connecting the two emitters, each oscillator operates independently, with its frequency...
Transistors Ql and Q2, with feedback provided via Cl from the collector of Ql to the base of Q2, forms a voltage-controlled oscillator (VCO). De- pending on the voltage applied to Q2 "s base, the VCO frequency ranges from around 60 Hz to 7.5 kHz. The instantaneous voltage applied to the base of Q2 is determined by the values of C2, R2, R3,...
A low-frequency, op-amp oscillator and a VCO, both configured from a single MC3405 ~dual op amp and dual comparator, are tbe major components in a siren circuit tbat can be made to produce various warbles and wails, or serve as an audio sweep generator.
Six preset controls and seven selector switches enable a vast range of different sounds to be produced and altered at will. Such sounds as steam trains chuffing, helicopters flying, bird chirping, and machine guns firing are possible, as well as the usual police sirens, phaser guns, and bomb explosions. The circuit incorporates an amplifier...
A pair of timer IC"s are the heart of a circuit that simulates the warbling bee-haw of a British police siren. One of the 555 timers, U2, is wired as an astable multivibrator operating at about 900 Hz. The other, Ul, operates at approximately 1 Hz. Its output at pin 3 is a square wave with a 50% duty cycle-on and off cycles of about 0.5...
The wailing sound of a siren is generated by a VFO consisting of Q1 and Q2. Capacitor C2 provides the feedback for the oscillator. The frequency of the oscillator is varied by the voltage applied to the base of Q1 through R3. When switch S1 is closed, capacitor Cl charges, thus increasing the oscillator frequency. When S1 is released,...
The simple circuit transforms the steady beep of an audible-signal device, such as a Mallory sonalert, into a distinctive warble or chirp. The value of R, C2 determines just what tone color you"ll get. With 1k the 1-I"F value shown, the circuit produces a warble similar to the ring tone of an inexpensive phone. A R, 10-I"F value produces a...
This circuit uses one of the LM389 transistors.to gate the power amplifier on and off by applying the muting technique. The other transistors form a cross-coupled multivibrator circuit that controls the rate of the square-wave oscillator.
"Hee-Haw" Electronic Siren
The oscillator based on IC2 is responsible for producing the sound. Its output is connected to the base of TRl,
6W Warble-Tone Siren
This circuit uses a CMOS chip and a VMOS FET amplifier for 6 W of audio output. 18 W of audio can be generated using
Alternate Tone Alarm Circuit
A two-tone generator that is alternately switched ON provides a high/low output as might be heard from a traffic vehicle like a police car or ambulance. IC1, CD4011, quad 2-input NAND gate is a two-tone oscillator in which each side, pins 1 through 7 and 8 through 13 set the tone frequencies. Changing the values of C9 and C] determines the...
Siren system circuit
The circuit uses a CA3130 BiMOS op amp as a multivibrator to control the siren's rate. A CA3094 used as a VCO is followed by a CA3082 transistor array used to drive a speaker. A "Manual" or "Auto" mode switch allows the user to select either intermittent or continuous siren operation, respectively.
Two NAND gates are used for the oscillator, and two as the control. If the two-tone speed needs to be altered, the 220 Âµ capacitors can be changed Oarger for slower operation). If the frequency of the oscillator is to be changed, the 0.2 and 0.1 /iF capacitors can be varied and the value of Rl can be increased. To change frequency range between...
House Alarm Loop Circuit
This circuit offers open and closed loop contacts (switches 1,2,3) that triggers the alarm ON and stays ON for 5 -10 minutes. The trigering delay (entrance/exit) is 27 seconds. This simple alarm circuit Has also a cancel button for reseting the circuit to stand-by mode again....
Motorcycle Alarm Number 2
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. Ron has used my Asymmetric Timer as the...
Any number of normally open switches may be used. Fit the mercury switches so that they 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 to protect removable panels and the lids of panniers etc. While at least one switch remains closed, the siren will sound....
Car Alarm and Immobilizer
The alarm is "set" by opening Sw1. It can be any small 1-amp single-pole change-over switch - but for added security you could use a key-switch. Once Sw1 is opened you have about 10 to 15 seconds to get out of the vehicle and close the door behind you. When you return and open the door the buzzer will sound. You have 10 to 15 seconds to move Sw1...
Home security system
The security system application and program offers a simple demonstration of the BASIC Serial Interface. By adding only a few door and window switches, a transistor, a siren, (see schematic) and a few lines of BASIC program (see program listing) the interface can become a multi-function security system. Please note, however, that it is a...
Wire Loop Alarm
This circuit is a simple wire loop alarm that can be used in doorways, hallways, or any other place the tripwire will be broken by intruders. The circuit has a built in siren, but it can be replaced by a relay to drive an external siren, commercial alarm, etc.
Siren Generator Schematic
No Description available.
IC 2 tones Siren
Double-tone Police sound Single-tone old ambulance sound This circuit is intended for children fun, and can be installed on bicycles, battery powered cars and motorcycles, but also on models and various games and toys. With SW1 positioned as shown in the circuit diagram, the typical dual-tone sound of Police or Fire-brigade cars is generated,...
The circuit board and switches must be protected from the elements. Dampness or condensation will cause malfunction. Without its terminal blocks, the board is small. Ideally, you should try to find a siren with enough spare space inside to accommodate it. Fit a 1-amp in-line fuse close to the power source. This protects the wiring. Instead of...
Car Alarm and Immobilizer
This circuit features exit and entry delays, an instant alarm zone, an intermittent siren output and automatic reset. By adding external relays you can immobilize the vehicle and flash the lights. One of the inputs is connected to the vehicle`s existing door-switches. This provides the necessary exit and entry delays. It`s usually sufficient to...
Motorcycle Alarm schematic
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. Ron has used my Asymmetric Timer as the basis...
Motorcycle anti-theft 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. The circuit is designed to use an electronic...
Automatic Intruder Alarm
This is a simple single-zone burglar alarm circuit. Its features include automatic Exit and Entry delays and a timed Bell/Siren Cut-Off. It`s designed to be used with the usual types of normally-closed input devices such as - magnetic reed contacts - micro switches - foil tape - and PIRs. But it can be Easily Modified to accept normally-open...
Motorcycle Alarm II
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.
An electronic siren made from discrete components. The sound 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 the 22k resistor. This voltage is applied to the base of the...
This circuit provides a good siren noise suitable for warding off robot-predators! Change the pitch by adjusting R2, and R5.
Surveillance Bug Circuits
Geiger–Müller meter circuit project
In this page we will show how you can simply construct such a meter, which is good to have one, to show not only the existence of radioactive materials but also the dangers arising from them. The Geiger–Müller counter can be compared to a photometer. The photometer measures the visible radiation. That is, light, while the gm meter measures the...
255W Valve RF Transmitter circuit
This transmitter of 255W is depended on the coils we put at it to work in both the middle and the short waves. The power in the antenna is 255W and includes 4 states. The first consists of the EF80 that works as a COLLPITS CLAPP oscillator. Frequency selection is done in a somewhat unusual way: Instead of the variable capacitor, it uses a...
Arduino DAC Signal Generator project
Once the circuit gets current, all variables are initialized and the loop function is continually running. Initially all LEDs are off and there is no signal at the output. By pressing the signal switch, the first light that shows the most signal is at the output and the D0-D7 terminals give the appropriate signal which, when passing from the...
Recording circuit of phone conversations using PC
This circuit is used to record telephone conversations on your landline telephone. All you will need is this small circuit and subscription of your PC. There are few times when we forget what we said or told us. So we need recording. Sometime, not many years ago, recording of this kind of conversation was done with a small tape recorder. The...
FM Micro-Transmitter Bug Surveillance Circuit
The transmitter we recommend to build is quite simple. It can even be built by a beginner. However, unlike the ease of construction and its small size, it is almost certain that it will impress you with its outstanding performance. Its autonomy is 12-15 hours, with a 9 volt battery and its range is from 100 to 300 meters depending on the...
Construction of 50Watt 8Ω two-way Hi-Fi Speakers
The presented speakers are distinguished for their small dimensions and their extraordinary sound. Our home space is often limited and prohibitive for large speakers. This limitation does not mean that we will stay without high Sound Quality. Its design is simple, low cost and is easy to construct. Speaker types are too many and are designed in...
GSM modem circuit with Wavecom WMOi3
Modems are devices that connect either remote devices to a computer, or two or more computers to each other. Their connection is usually wired. The GSM modem we present is wireless. It can connect two computers, a computer with the internet or even be the central unit for a data acquisition system. Generally the construction is a GSM phone...
1W UHF Linear Amplifier with BLW33
This circuit is an amplifier for small transmitters operating in the UHF band, specifically in the 450-800MHz range. The amplifier works in class A and we used the well-known Philips BLW33 transistor for its manufacture. The construction, although simple, can be said to be quite critical due to the high frequency singularity. To achieve this, a...
8W Amplifier with TDA2003 circuit
Many times a small amplifier is needed to meet the needs of small spaces. This amplifier can be either mono or stereo, with this circuitry you can comfortably drive two small speakers. To build the amplifier you do not need anything but a few materials and a small power supply. The power of the amplifier, although low power, will solve many...
Digital Signal Integrity
Interconnection and Timing of Digital Circuits
CMOS Circuits Tutorial
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