Showing posts with label 5. Show all posts
Showing posts with label 5. Show all posts

Friday, April 12, 2013

5 Zone Alarm System

This is a complete alarm system with 5 independent zones suitable for a small office or home environment. It uses just 3 CMOS ICs and features a timed entry / exit zone, 4 immediate zones and a panic button. There are indicators for each zone a "system armed" indicator. The schematic is as follows:


5 zone alarm


Circuit Notes
Each zone uses a normally closed contact. These can be micro switches or standard alarm contacts (usually reed switches). Suitable switches can be bought from alarm shops and concealed in door frames, or window ledges.

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 immunity is provided for long wiring runs by the input capacitors, C1-C5. C7 and R14 also form a transient suppressor. The key switch acts as the Set/Unset and Reset switch. For good security this should be the metal type with a key.

Operation
At switch on, C6 will charge via R11, this acts as the exit delay and is set to around 30 seconds. This can be altered by varying either C6 or R11. Once the timing period has elapsed, LED6 will light, meaning the system is armed. LED6 may be mounted externally (at the bell box for example) and provides visual indication that the system has set. Once set any contact that opens will trigger the alarm, including Zone 1. To prevent triggering the alarm on entry to the building, the concealed re-entry switch must be operated. This will discharge C6 and start the entry timer. The re-entry switch could be a concealed reed switch, located anywhere in a door frame, but invisible to the eye. The panic switch, when pressed, will trigger the alarm when set. Relay contacts RLA1 provide the latch, RLA2 operate the siren or buzzer.
 
 
 http://streampowers.blogspot.com/2012/07/5-zone-alarm-system.html
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Monday, April 8, 2013

5 to 15V Regulated Power Supply Rise

Regulated Power Supply
This project is a normal DC regulated power supply that is a variable DC voltage range from 5V to 15V. It can supply current up to  400mA to power the various circuits for your electronic projects. The voltage output is varied by using the potentiometer V.R1. In this circuit, the input line power supply is designed for 240V.A.C. If 110VAC input is used, alter the ratings of the varistor to 150VAC & the transformer ratio to 110V/12V. 

Fuse F1 is used as a protection in case theres any short circuit in the circuit. Varistor V1 is connected in parallel to the input of the line voltage to clamp the surge voltage from the line to a reasonable level that helps to protect the transformer & other circuitry. One time the voltage level surge to a high level beyond the ability of the varistor to absorb it, fuse F1 or varistor V1 or both will burn. If this circuit failed after a period of operation, check that the fuse & the varistor are still in nice condition or else replace them.

Diodes D1, D2, D3 and D4 are used to rectify the 12V.A.C voltage to DC voltage. Electrolytic capacitor E1 is used as a smoothing capacitor to reduce the ripple of the DC voltage. The DC voltage is fed in to the input of 7805 regulator where the output DC voltage is obtained. Changing the worth of VR1 will alter the output of the DC voltage. Capacitor C1 is used to filter out high frequency part from the power supply.


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Sunday, April 7, 2013

LA3600 5 Band Equalizer Circuit

LA3600 | 5 Band Equalizer CircuitOne type of regulator of tone / tone controls are the Audio Graphic Equalizer. Audio Graphic Equalizer have 2 kinds in my opinion. Namely Audio Graphic Equalizer Bar and the type of parametric type is often called parametric equalizer.

Audio Graphic Equalizer In the article this is the type of bar with 5 channels using IC LA3600. IC LA3600 is a single chip "Audio Graphic Equalizer 5 channel" that is designed specifically for the equalizer five channels. Because IC LA3600 is a special design of the equalizer circuit to make this a simple equalizer. Figure series of Audio Graphic Equalizer 5 channels with IC LA3600 as follows.

5 channel equalizer
Equalizer Schematic

Audio Graphic Equalizer circuit with IC LA3600 above can control the audio frequencies from 108 Hz to 10.8 KHz. Audio frequency which is controlled by this equalizer was 108 HZ, 343 Hz, 1.08 KHz, 3.43 KHz and 10.8 KHz. The frequency of that frequency is set based on the value of 2 pieces of capacitors in each chanelnya. So for instance want to change the center frequency of each channel value of 2 pieces of the capacitor can be changed as desired.
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