Published:2012/9/4 20:53:00 Author:Ecco | Keyword: 5V , CAPACITANCE, TOUCH , ACTIVATED MOMENTARY SWITCH
This circuit is discussed in more detail in the section on Capacitance Proximity Switch Technology. The circuit is powered from a standard +5v supply. It has both a source and sink output that change state whenever a metal button connected to the circuit is touched. An earth ground reference is required.
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Published:2012/9/4 20:53:00 Author:Ecco | Keyword: Wire , Security , Loop Alarm
A wire loop is used to protect valuable objects in this alarm circuit. The circuit is powered by a 9v battery.
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Published:2012/9/4 20:52:00 Author:Ecco | Keyword: ELECTRIC , FIELD DISTURBANCE MONITOR, Alarm Discriminator, + Battery Monitor
This schematic is the power supply and front-end sections of the field monitor that is discussed in more detail at Electric Field Disturbance Monitor. The system can detect human and animal motion by the electric fields they disturb.
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Published:2012/9/4 20:51:00 Author:Ecco | Keyword: Ultracapacitor , Voltage Limiting
Supercapacitors are working their way into more and more applications where electrical energy needs to be stored. These robust devices can be charged and discharged 1000s of times and will typically outlast a battery. Many supercap manufacturers claim a life span of 10 years or more. A supercapacitor is often chosen to supply power to low current load for many hours at a time, recharged by a solar panel.
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Published:2012/9/4 20:48:00 Author:Ecco | Keyword: HIGH INTENSITY , LINE POWERED, LED FLASHER
There are times when you would like to generate an intensely bright flash of light using electrical power from the AC line. The circuit below can drive a one to three watt power LED with about 350ma of peak current. Since the circuit drives the LED with a constant current, any LED color can be used. I have also shown how you could use an array of 7 LEDs, wired in parallel. This array may not produce as much light as the single power LED but the array would be cheaper to build.
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Published:2012/9/4 20:47:00 Author:Ecco | Keyword: FLASHING LED, POWER INDICATOR, DRAWS , LOW CURRENT
This circuit flashes a power indicator LED to keep the average current low
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Published:2012/9/4 20:46:00 Author:Ecco | Keyword: MACHINE POWER, LOSS BEEPER
For some medical equipment it is important for an operator when power is lost to the machine. The beeper is powered from a 9v battery and requires the machine to have a power switch with a third set of contacts.
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Published:2012/9/4 20:45:00 Author:Ecco | Keyword: Reflected , Infrared Light, Switch
Infrared light reflected off a finger is used to activate this switch circuit. Drawing only 30uA from a 3v supply, this circuit will detect a human finger with a range of about 1 inch. The sensor uses an inexpensive infrared LED and a matching photo diode.
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Published:2012/9/4 20:45:00 Author:Ecco | Keyword: 12V , TOUCH SWITCH, EXCITER CIRCUIT
This circuit is designed to generate a 20KHz pseudo sine wave signal that can power about 50 remote touch activated switch circuits. It can support a cable length of about 2500 feet. A typical remote switch circuit is also shown as well as a receiver circuit for those switches.
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Published:2012/9/4 20:44:00 Author:Ecco | Keyword: +5v, Powered Charge Pump , Battery Charger
The circuit below will trickle charge a four cell pack of AA or AAA NiMH batteries. The circuit draws current from the +5v available a USB connection and pumps about 70ma of current into the battery. This should be enough current to fully charge a pack of 2500ma-hour cells in about 36 hours. The circuit uses a single 74HC14 hex Schmitt trigger inverter in conjunction with a voltage doubler charge pump circuit.
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Published:2012/9/4 20:43:00 Author:Ecco | Keyword: CAPS , PROVIDE VOLTAGE BOOST, SERIES REGULATOR
This circuit adds some capacitors and diodes to a traditional transformer type series regulator circuit to extend the normal operating range. It can insure regulation during low line voltage conditions or it can squeeze a few more watts out of a plug-in-the-wall power adapter power supply.
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Published:2012/9/4 20:43:00 Author:Ecco | Keyword: Fully Isolated , 50/60Hz , Sync Generator
This circuit will produce a single pulse at the zero voltage cross points of the power line voltage. An opto-coupler provides a very safe 5KV isolation.
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Published:2012/9/4 20:39:00 Author:Ecco | Keyword: 9v, POWERED, XENON , PHOTOFLASH Controller
This 9v battery powered circuit is designed for remote control flash needs. A charge control circuit turns off the high voltage generator when the photoflash capacitor is fully charged. A neon lamp is included to indicate when the system is ready to flash.
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Published:2012/9/4 20:32:00 Author:Ecco | Keyword: Button , Battery Cell, Internal Resistance , Measurement Circuit
The open cell voltage of a small silver oxide button cell battery remains very close to 1.5 volts over most of the life of the cell. However, there is a relationship between battery health and the internal resistance of the cell. This circuit when used in conjunction with an oscilloscope will measure the internal resistance. You will have to use a known good cell as a reference.
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Published:2012/9/4 20:32:00 Author:Ecco | Keyword: 6V, NiCd/NMH Battery, Test Circuit, 10 Amp , Constant Current Load
I designed this circuit to test rechargeable six volt battery packs under constant current conditions. As designed, the circuit applies a 10 amp load to the battery pack. A heat sink must be used on the main power transistor.
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Published:2012/9/4 20:27:00 Author:Ecco | Keyword: THREE VOLT , LOW BATTERY VOLTAGE , FLASHER
This circuit is designed to monitor two alkaline cells (3v) that form the battery often used in portable electronic equipment. It use an inexpensive IC from Panasonic that is connected to an efficient LED flashing circuit. When the battery voltage drops below a certain point the circuit flashes the LED.
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Published:2012/9/4 20:25:00 Author:Ecco | Keyword: Fake , Car Alarm , Light
Whenever the car?s ignition is turned off, this circuit activates a flashing LED, which can be positioned to appear as an active alarm system.
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Published:2012/9/4 20:25:00 Author:Ecco | Keyword: Automotive Electrical , Voltage Indicator
This circuit will indicate if an automotive electrical circuit has zero volts or 12 volts present.
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Published:2012/9/4 20:24:00 Author:Ecco | Keyword: Pushbutton , Activated, Service Request, Beeper
A single press of a pushbutton switch turns on a beeper for one second but can?t be activated again for 60 seconds.
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Published:2012/9/4 20:23:00 Author:Ecco | Keyword: Piezoelectric , Vibration, Sensor, Activates , Switch
An inexpensive piezoelectric wafer is used to detect vibration and when the vibration is sufficient a switch is activated.
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