Showing posts with label system. Show all posts
Showing posts with label system. Show all posts
Wednesday, September 24, 2014
Video Switch for Intercom System
Video Switch for Intercom System Circuit Diagram. Nowadays a lot of intercom units are equipped with video cameras so that you can see as well as hear who is at the door. Unfortunately, the camera lens is perfectly placed to serve as a sort of support point for people during the conversation, with the result that there’s hardly anything left see in the video imagery. One way to solve this problem is to install two cameras on the street side instead only one, preferably some distance apart. If you display the imagery from the two cameras alternately, then at least half of the time you will be able to see what is happening in front of the door. Thanks to the video switch module described here, which should be installed on the street side not too far away from the two cameras, you need only one monitor inside the house and you don’t need to install any additional video cables.
Circuit diagram :
Video Switch for Intercom System Circuit Diagram
Along with a video switch, the circuit includes a video amplifier that has been used with good results in many other Elektor projects, which allows the brightness and the contrast to be adjusted separately. This amplifier is included because the distance between the street and the house may be rather large, so it is helpful to be able to compensate for cable attenuation in this manner. The switch stage is built around the well known 4060 IC, in which switches IC2a and IC2d alternately pass one of the two signals to the output. They are driven by switches IC2b and IC2c, which generate control signals that are 180 degrees out of phase. The switching rate for the video signals is determined by a clock signal from an ‘old standby’ 555 IC, which causes the signals to swap every 2 seconds with the speciļ¬ed com ponent values.
Naturally, this circuit can also used in many other situations, such as where two cameras are needed for surveillance but only one video cable is available.
Wednesday, June 12, 2013
Alarm Circuit for 5 Zone Alarm system
5 Zone Alarm Circuit
My advice is to print off a copy of the schematic then to systematically list all components of one type. Start with resistors, write down their values from the schematic and place a pencil mark against the component on the schematic. Repeat until all components have been ticked. So reading from the schematic:
There are 6 100k resistors, R1, R3, R5, R7, R9, R14.
6 1k resistors, R2, R4, R6, R8, R10, R12.
1 220k resistor R11
1 10k resistor R13. All resistors will be 1/4 watt at 5 or 10& tolerance.
5 100n capacitors, C1 to C5. These may be polyester or disc ceramic, 50V working or higher.
C6 1 100uF capacitor. This should be electrolytic have a working voltage of at least 25Volts or higher.
C7 1 1uF capacitor. Electrolytic as for C6.
3 1N4148 Diodes, D1, D2, D3 which should be readily obtainable.
1 1N4001 diode D4.
5 LEDs LED1 - LED5. Colour is not important but you may like to use the same colour for zones 2 to 5 and a different colour for zone 1, the entry, exit delay.
1 2N3904 transistor, Q1.
1 4050B CMOS IC for IC1. Note that CMOS 4050BE may also be used.
1 4072B CMOS, IC2
1 4082B CMOS IC, IC3. Note that unused inputs on ICs 2 and 3 should be connected to earth and that the power pins must be connected.
1 Relay with 2 changeover contacts. The coil needs to match the circuit, i.e. 12V coil, the relay contacts must be suitable for the load. As the load is a piezo buzzer, there will be little load current, so a miniature or sub-miniature relay may be used.
1 keyswitch
1 NO PBS (for the panic switch).
1 reed relay ( for the re-entry switch).
5 NC contact switches. These can be bought from alarm shops and fitted to doors or windows etc.
That completes the full list of components for this circuit. It is an easy matter, and can be applied to any circuit. With experience you just look at the circuit and order all the components required.
Where can I get a parts list for a particular circuit?
Answer: From the schematic, read on to find out how.
If a circuit contains less than 20 components, you dont need a separate parts list, you can obtain them straight from the schematic. If the circuit is larger than this, something may be missed, so it is handy if a parts list is available.
Prerequisites:
Before you start to write down the components, there are certain things you must know about each component. This applies to all schematics, not just the circuits on this site. This additional information is listed below :
Resistors:
Unless stated, any resistor in a circuit will be rated at 1/4 watt. This is a standard wattage and all manufacturers supply 1/4 or 1/3 watt resistors. Higher wattage resistors may be used, but are more expensive than the 1/4 watt type. Although seldom stated a resistor does have a maximum voltage rating of 1000 Volts (not by ohms law) but due to the material it is made from. If the circuit is a high voltage circuit, then special high voltage resistors must be used.
Tolerance Unless stated assume all resistors in a circuit have10% tolerance. Buying 1/3w or 1/4w resistors at 5 or 10% in bulk may save money if you are a serious hobbyist.
Capacitors:
There are many different types of capacitors, electrolytics, polyester, silver mica, tantalum bead etc. Some have different characteristics and offer advantages in particular circuits.
Working Voltage The working voltage of a capacitor MUST exceed the working voltage of a circuit. This is of greatest importance with large value electrolytics, where excess voltage may cause the chemicals in the capacitor to overheat or explode. For any given power supply I would recommend that the voltage of the capacitor be at least 3 times higher than the nominal voltage of the power supply.
Tolerance Capacitors vary widely in tolerance, electrolytics may be +/- 20% of their rated capacitance, whereas ceramic plate capacitors can be made to within 5% of their nominal value.
Capacitors in Circuits:
Unless stated on a schematic, I would recommend the using capacitors as follows:
Ceramic Disc: Decoupling logic circuits, or radio circuits
Ceramic Plate: Timing circuits or other close tolerance circuits
Electrolytic: Use in power supplies and audio circuits, or where large capacitance values are required.
Polyester Film: Decoupling circuits, RF circuits
Tantalum: Low leakage circuits, timing circuits
Inductors and Transformers:
An Inductor in its simplest form is just a coil of wire (air-spaced), however it may be wound on a core that is either iron or ferrite to increase its inductance, or wound onto a former to make a transformer. There are also high frequency transformers known as IFTs these will have a particular resonant frequency and best suited to a radio design. Inductors for a radio circuit will always be specified on the schematic. Transformers for power supplies circuits will always be specified on a schematic with the correct choice of primary and secondary ratings.
Diodes and Transistors:
The recommended first choice of transistor or diode will be stated on the circuit. If the component cannot be obtained locally then a substitute part may be used, usually chosen from a catalog or substitute handbook. If choosing an alternative part make sure the ratings match those of the original circuit.
Switches and Relays:
Switches and relays, being mechanical in nature, can be unreliable components so if you want reliability dont buy the cheaper switches. Switch and relay contacts must have voltage and current ratings greater than the load they will switch, this will be stated on the diagram. If not stated then use a switch or relay with contacts that can handle the voltage and current of the circuit.
Read More..
My advice is to print off a copy of the schematic then to systematically list all components of one type. Start with resistors, write down their values from the schematic and place a pencil mark against the component on the schematic. Repeat until all components have been ticked. So reading from the schematic:
There are 6 100k resistors, R1, R3, R5, R7, R9, R14.
6 1k resistors, R2, R4, R6, R8, R10, R12.
1 220k resistor R11
1 10k resistor R13. All resistors will be 1/4 watt at 5 or 10& tolerance.
5 100n capacitors, C1 to C5. These may be polyester or disc ceramic, 50V working or higher.
C6 1 100uF capacitor. This should be electrolytic have a working voltage of at least 25Volts or higher.
C7 1 1uF capacitor. Electrolytic as for C6.
3 1N4148 Diodes, D1, D2, D3 which should be readily obtainable.
1 1N4001 diode D4.
5 LEDs LED1 - LED5. Colour is not important but you may like to use the same colour for zones 2 to 5 and a different colour for zone 1, the entry, exit delay.
1 2N3904 transistor, Q1.
1 4050B CMOS IC for IC1. Note that CMOS 4050BE may also be used.
1 4072B CMOS, IC2
1 4082B CMOS IC, IC3. Note that unused inputs on ICs 2 and 3 should be connected to earth and that the power pins must be connected.
1 Relay with 2 changeover contacts. The coil needs to match the circuit, i.e. 12V coil, the relay contacts must be suitable for the load. As the load is a piezo buzzer, there will be little load current, so a miniature or sub-miniature relay may be used.
1 keyswitch
1 NO PBS (for the panic switch).
1 reed relay ( for the re-entry switch).
5 NC contact switches. These can be bought from alarm shops and fitted to doors or windows etc.
That completes the full list of components for this circuit. It is an easy matter, and can be applied to any circuit. With experience you just look at the circuit and order all the components required.
Where can I get a parts list for a particular circuit?
Answer: From the schematic, read on to find out how.
If a circuit contains less than 20 components, you dont need a separate parts list, you can obtain them straight from the schematic. If the circuit is larger than this, something may be missed, so it is handy if a parts list is available.
Prerequisites:
Before you start to write down the components, there are certain things you must know about each component. This applies to all schematics, not just the circuits on this site. This additional information is listed below :
Resistors:
Unless stated, any resistor in a circuit will be rated at 1/4 watt. This is a standard wattage and all manufacturers supply 1/4 or 1/3 watt resistors. Higher wattage resistors may be used, but are more expensive than the 1/4 watt type. Although seldom stated a resistor does have a maximum voltage rating of 1000 Volts (not by ohms law) but due to the material it is made from. If the circuit is a high voltage circuit, then special high voltage resistors must be used.
Tolerance Unless stated assume all resistors in a circuit have10% tolerance. Buying 1/3w or 1/4w resistors at 5 or 10% in bulk may save money if you are a serious hobbyist.
Capacitors:
There are many different types of capacitors, electrolytics, polyester, silver mica, tantalum bead etc. Some have different characteristics and offer advantages in particular circuits.
Working Voltage The working voltage of a capacitor MUST exceed the working voltage of a circuit. This is of greatest importance with large value electrolytics, where excess voltage may cause the chemicals in the capacitor to overheat or explode. For any given power supply I would recommend that the voltage of the capacitor be at least 3 times higher than the nominal voltage of the power supply.
Tolerance Capacitors vary widely in tolerance, electrolytics may be +/- 20% of their rated capacitance, whereas ceramic plate capacitors can be made to within 5% of their nominal value.
Capacitors in Circuits:
Unless stated on a schematic, I would recommend the using capacitors as follows:
Ceramic Disc: Decoupling logic circuits, or radio circuits
Ceramic Plate: Timing circuits or other close tolerance circuits
Electrolytic: Use in power supplies and audio circuits, or where large capacitance values are required.
Polyester Film: Decoupling circuits, RF circuits
Tantalum: Low leakage circuits, timing circuits
Inductors and Transformers:
An Inductor in its simplest form is just a coil of wire (air-spaced), however it may be wound on a core that is either iron or ferrite to increase its inductance, or wound onto a former to make a transformer. There are also high frequency transformers known as IFTs these will have a particular resonant frequency and best suited to a radio design. Inductors for a radio circuit will always be specified on the schematic. Transformers for power supplies circuits will always be specified on a schematic with the correct choice of primary and secondary ratings.
Diodes and Transistors:
The recommended first choice of transistor or diode will be stated on the circuit. If the component cannot be obtained locally then a substitute part may be used, usually chosen from a catalog or substitute handbook. If choosing an alternative part make sure the ratings match those of the original circuit.
Switches and Relays:
Switches and relays, being mechanical in nature, can be unreliable components so if you want reliability dont buy the cheaper switches. Switch and relay contacts must have voltage and current ratings greater than the load they will switch, this will be stated on the diagram. If not stated then use a switch or relay with contacts that can handle the voltage and current of the circuit.
Sunday, June 2, 2013
Painless Wiring Perfect Jeepengine Management System
Painless Wiring Fuel Injection Harness.
Painless Fuel Injection Wiring Harness For 1996 1999 Chevy Pick Up.
Painless Wiring Perfect Jeep 4 0l Engine Management System.
Painless Wiring Pw Pw60026 60526 W Pcm Tcm For 4 8l 5 3l 6 0l.
Painless Wiring.
Painless Wiring 80151 Hdlt Sw Alum Knob W Dimmer.
Painless Wiring 10206 Painless Performance 18 Circuit 1967 72.
00 2000 Chevrolet K3500 Painless Wiring Engine Control Module Wiring.
Painless Wiring Headlight Relay.
Painless Fuel Injection Wiring Harness For 1992 1995 Gmc Safari.
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