Rain alarm schematic circuit diagram
FIG. 1 is a circuit diagram of it, it is in the audio circuit from the resistance between the two leads to a probe to rain alarm. Fig. 2 with CCL to make a probe connected to t
Fire Alarm schematic design
Explanation Here is a simple fire alarm circuit based on an LDR fire detection sensor. Smoke generated during circuit generates an audible alarm, fire smoke in case of fire. Al
Door alarm circuit with a time of recognition NE555
Door alarm here with a time recognition, the owner opened the door is normally open the door, open the door to complete the action within the general 30s, so it does not alarm,
Break burglar alarm circuit II
Ding for the circuit principle: care, vs SCR trigger grounded, it is in the off state. When someone leads A burglar broke, the SCR trigger end to give a trigger voltage is turn
The circuit generates a warble-tone alarm signal that simulates the sound of a British police siren. IC1 is wired as an alarm generator and IC2 is wired as a 1 Hz astable multivibrator. The output of IC2 is used to frequency modulate IC1 via R5.
The single-chip, burglar -alarm circuit shown uses a dual 556 timer, draws 10 mA of standby current, and generates a pulsing alarm signal that conserves battery energy. Once activated, the alarm wilLremain on, independent of the subsequent state of any of the sensors. The sensors support both deferred and immediate-action modes. You can...
False alarms produced by semiconductor failure are impossible with this burglar-alarm circuit equipped with relays. What"s more, the circuit is virtually immune to false triggering. With a standby current of less than 0.1 mA, the circuit offers all the features an alarm needs: entry and exit delays, a timed alarm period, and automatic reset...
The heart of the circuit is a 555 oscillator /timer, Ul, configured for monostable operation. The output of Ul at pin 3 is tied to the gate of SCRl. As long as Sl-S5, which are connected to the trigger input of Ul, are open, the circuit remains in the ready state, and does not trigger SCRl into conduction. Because the relay is not energized,...
The tracer, consisting of both a transmitter and receiver, is designed to follow a closed-loop wire or cable system. It follows an induced voltage path created by feeding a low-current, audio-frequency signal through the cable. When the pick-up coils come within close proximity of the current -carrying cable, a small voltage is generated...
Burglar Alarm With Timed Shutoff
When SI (sensor) is closed, power is applied to U2, a dual timer. After a time determined by C2, CI is ene
Home Security System
This alarm circuit activates when SI through S5 are activated. This lights LED1 and activates Ql via IC1C and IC1D. RY
Warble Alarm Circuit
This circuit uses a 556 to first generate a low frequency square wave, that is modulated to produce two alternate tones of about 400 and 500 Hz. Circuit generates warble alarm of European emergency vehicles.
Audio Alarm Circuit
In the circuit, U1 amplifies the audio picked up by the condenser microphone. Resistor Rl limits current, while R2 and R3 center the output of the amplifier to %B+ to allow a single-ended supply to be used. Diodes D1 and D2 rectify the output of Ul, and C3 filters the resulting pulsing dc. Thus, a dc voltage that is proportional to the ambient...
Piezoelectric Alarm Circuit
The alarm uses a fixed-frequency piezoelectric buzzer in conjunction with the cadmium-sulfide (CDS) cell and the two-transistor circuit to provide a unique effect. Whenever light reaches the CDS photo-electric cell, the alarm is silent. But when no light strikes the cell, transistor Ql turns on, and the circuit emits a high-pitched tone.The...
Burglar Chaser Circuit
The burglar chaser makes a great accessory for any alarm system. It creates brilliant flashes of white light and a loud, irritating sound from a metal horn buzzer. Transformer T1 is connected to Ql, Rl, and R2 to form a blocking oscillator. This creates a 6-Vac signal on the primary of Tl. Because of Tl`s large ratio of turns from primary to...
Carrier-Current Baby-Alert Transmitter Circuit
The baby-alert transmitter is built around an LM324 quad op amp (Ul), two LMC555CM CMOS oscillator/timers (U2 and U3), and a few support components. The transmitter sends a signal on receipt of a sound at MIC1.
Carrier-Current Baby-Alert Receiver Circuit
The baby-alert receiver is comprised of three transistors: Q2, which is configured as a high-gain linear amplifier; Q3, which serves as both an amplifier and detector; and Q4. which is essentially used as a switch; and a few additional components.
Flash Signal Alarm Circuit
This circuit is useful if you need a low-energy flashing alarm. The 200 to 400-dc supply should have enough internal resistance to charge the 0.5 capacitor between flashes, about 2 or 3 time constants, which means about 500 kQ to 1 for a 1-s rate.
Proximity Alarm I Circuit
IC1 contains several oscillators and an amplifier. The low-frequency audio-signal oscillator is used to supply an input to the amplifier. That signal is the audio tone that is amplified, then supplied to the speaker by the amplifier. The high-frequency oscillator is purposely set to be very unstable. It is dormant or off` until the...
5V Dial Tone Circuit Circuit
This circuit uses inexpensive, common components to generate a precise dial tone for phone applications (see the figure). Ul (an Intel 82C54 timer-counter) generates 350 and 440Hz square waves that are filtered by Rl/Cl and R,JC2, and mixed together by resistors R2 and R4. An operational amplifier configured as a 395-Hz, Sallen-Key,...
Simple House Alarm circuit
This house alarm circuit has open and closed loop sensor and has self shutdown function. The delay after trigering can be adjusted from 1 minute to 12. The delay before trigering is 13 seconds. Offcourse all this timmings can be change with litle changes to few passive parts.
This inexpensive dc supply-voltage monitor sounds a warning when the voltage falls below a preset value. It is ideal for monitoring rechargeable batteries since it draws only a few microamperes when not sounding. The voltage at which the alarm sounds is determined by the zener diode. When the voltage falls below the zener voltage, the alarm...
This circuit simulates the sound of an American police siren. IC2 is wired as a low frequency astable that has a cycling period of about 6 seconds. The slowly varying ramp waveform on Cl is fed to pnp emitter follower Ql, and is then used to frequency modulate alarm generator IC1 via R6. IC1 has a natural center frequency of about 800Hz.
Timer with alarm
The circuit has two ranges: 10 sees to 5 mins and 1 min to 80 mins. It can be powered by a 9-V battery. With the LED connected as shown a reasonable frequency of flashing occurs throughout the range of operation.
Clever Car alarm circuit
When this car alarm circuit is activated it stays activated for 80 seconds. It has 15 seconds delay for the driver to enter and deactivate. and All timmings can be altered easilly...
One circuit alarm phase
3-phase power, would endanger the electrical equipment (especially asynchronous motor) security, in order to detect phase failure, it can be made with a broken alarm. Circuit s
Portable alcohol detector alarm circuit
Circuit works: QM-NJ9 is alcohol sensor. QM-NJ9 contact after the odor of alcohol, the resistance value A, B between the reduced
The circuit has a built-in, self-arming feature. The driver turns off the ignition, presses the arm button on theComputalarm, and leaves the car. Within 20 seconds, the alarm arms itselfâ€”all automatically! The circuit will then detect the opening of any monitored door, the trunk lid, or the hood on the car. Once activated, the circuit remains...
Gas stove flame alarm circuit
The circuit shown is the second natural gas (gas) stove flame alarm. After the gas stove ignited normal combustion, close the power switch S. Photoresistor RG due
Mains voltage bidirectional limit alarm protection circuit diagram
When the alarm protection can be higher or lower than the predetermined value in the mains voltage, sound and light alarm,
Power disconnection alarm circuit diagram
Circuit operation principle of the device shown in Figure 13. When the barbed wire Fe intact, LSE's O, feet collusion between its pin output high,
Multi power failure alarm circuit
Circuit works: This is an AC blown fuse alarm. When BX is not when blown, 220 V AC voltage through a VD1 VD4 bridge rectifier, R1 limiting buck, after DW 6V DC
Surveillance Bug Circuits
Low Cost Pulse Generator circuit
This pulse generator produces square pulses from 1Hz to 100KHz with adjustable pulse width of nearly 0-100%. The generator is powered with a voltage of 5-15V and is therefore suitable for both TTL and CMOS circuits. If you want to measure the response of an amplifier or give timing pulses to a variable frequency digital circuit or drive a pulse...
Key Code Combination High Security Door Lock
This project is an electronic lock with many combinations that you can easily change and opens only with the correct combination of four consecutive numbers. The big advantage of the electronic lock is that the four numbers must be entered in the correct order one after the other. If a number is wrong then the circuit automatically resets to its...
Induction Balance Gold Metal Detector Circuit
This circuit really is the simplest inducer balancing metal detector (IB, Inductlon Balance) that can be built. The LB metal detection method has a satisfactory depth of penetration and good distinction between iron-based and noble metallic objects. Several metal detectors are available in the market, but their price is often prohibitive for...
Secret High Power Free Energy Circuit (AEC)
This is a Tesla/joule thief hybrid circuit that its inventor claim to produce 90 times the input power! The circuit can be self looped and can provide 1050W of power. from the 1050W only the 11.6W will loop back to supply the joule thief. If you remove the bridge rectifier and the C capacitor you can use the circuit with high frequency AC...
High Power Full Bridge Flyback Driver circuit
You need to find a reliable full bridge driver to drive your flyback transformer? Well, This is your final stop. There are many flyback drivers schematics out there, but most of them will not last for long. It is common known that famous ZVS invented by Vladmiro Mazilli, is the most reliable flyback driver as it uses the resonant zero voltage...
High Precision Digital Pulse Meter Circuit
This small device, intended primarily for modellers, allows an instant reading of the time I of a pulse in ms. It can, for example, measure the position of the servomotors, about 1 to about 2 ms, or make repetitive or non-pulsed measurements, such as closing or opening times of any instrument, parasitic abnormality. The diagram just describes...
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