Electrical Current Indicator

Published:2012/9/6 20:04:00 Author:Ecco | Keyword: Electrical Current , Indicator

I designed this circuit as a simple current indicator for any load ranging from 40 watts to 250 watts. The circuit turns on a small LED, whenever it detects current flowing to a remote load. Source: discovercircuits   (View)

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PULSE PERIOD TO VOLTAGE CONVERTER

Published:2012/9/6 19:58:00 Author:Ecco | Keyword: PULSE PERIOD , VOLTAGE CONVERTER

This is a test circuit converts a square wave input signal into a voltage. But, the voltage produced is proportional to the time between edges (period) of the signal, not the frequency. The range is from 100uS to to 10mS, which produces a voltage from 100mV to 10 volts. Other scale factors are also possible. The circuit is powered from single 15v supply and uses inexpensive parts. It is great when a signal's period instead of its frequency needs to be monitored. Source: discovercircuits   (View)

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TEMPERATURE SENSOR WITH 4 TO 20mA CURRENT LOOP

Published:2012/9/5 21:08:00 Author:Ecco | Keyword: TEMPERATURE SENSOR, 4 TO 20mA , CURRENT LOOP

I designed a circuit similar to this one years ago to accurately measure the air temperature inside a building 1000s of feet from a control room. The circuit uses a very robust current loop method. It uses a highly accurate semiconductor temperature sensor and an equally accurate voltage reference. The circuit includes a diode bridge, so it is polarity independent. By using the component values indicated, the circuit should not require calibration. It has a range from ?40F to +120F and an accuracy of +/- one degree F. Source: discovercircuits   (View)

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Energy Harvesting Using a Current Transformer -- January 17, 2010

Published:2012/9/5 21:06:00 Author:Ecco | Keyword: Energy Harvesting , Current Transformer

Energy harvesting is all the rage these days. With some modern electronics, information from low power sensors can be sent to a distant data collection point using a low power RF transmitter. To power these remote sensors, various energy sources can be tapped into. Machine vibration, temperature differences, ambient light and stray RF have all been used as low power energy sources. Sometimes, the sensors are located near AC power cables. Rather than making a direct connection to those cables, an AC current transformer, such as the one shown below, can be used to capture a bit of power. Source: discovercircuits   (View)

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Computer Controlled 100ma Current Source (July 11, 2008)

Published:2012/9/5 21:03:00 Author:Ecco | Keyword: Computer Controlled, 100ma, Current Source

Often in industrial control systems a constant current source is needed, which is controlled by a computer and referenced to circuit ground. The circuit below converts a zero to 5v signal from a computer?s analog output into a current, with a full scale of 100ma. The circuit shown requires a 9v DC supply but any voltage from 9v to 12v will work. Source: discovercircuits   (View)

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5 VOLT MOMENTARY OPERATION TOUCH SWITCH

Published:2012/9/5 21:02:00 Author:Ecco | Keyword: 5 VOLT, MOMENTARY OPERATION , TOUCH SWITCH

This simple circuit uses a single IC to form a nice touch switch circuit. A single transistor forms the remote active switch sensor. Multiple switches can be wired in parallel. The switch circuit can be located about 500 feet from the control circuit. Source: discovercircuits   (View)

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Pushbutton Activated Service Request Beeper

Published:2012/9/5 21:01:00 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. Source: discovercircuits   (View)

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1.5V TOUCH ACTIVATED SWITCH

Published:2012/9/5 20:58:00 Author:Ecco | Keyword: 1.5V, TOUCH , ACTIVATED SWITCH

This circuit provides about one watt of non-isolated DC power for an automotive type 12v LED array lamp in addition to a standard incandescent table lamp. Source: discovercircuits   (View)

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On/Off Flip/flop Circuit with Automatic Timeout

Published:2012/9/5 20:54:00 Author:Ecco | Keyword: On/Off, Flip/flop , Automatic Timeout

This circuit is ideal when a device needs to be turned on and off with a single pushbutton switch, but also needs to turn itself off after some period of time. With the components shown, the output will stay on for only about 20 seconds. Source: discovercircuits   (View)

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CMOS SCHMITT TRIGGER IC MAKES VCO

Published:2012/9/5 20:52:00 Author:Ecco | Keyword: CMOS , SCHMITT TRIGGER , IC, VCO

By changing the supply voltage fed to a classic 4584 Schmitt trigger type oscillator, the oscillator frequency can be changed over a range of 50:1. A 74HCU04 inverter is used at the output of the 4584 to maintain a constant TTL logic level signal. Source: discovercircuits   (View)

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Water Flowing in Pipe Indicator

Published:2012/9/5 20:43:00 Author:Ecco | Keyword: Water Flowing , in Pipe , Indicator

The vibrations associated with water flowing through a pipe are picked up by an inexpensive piezoelectric wafer. The signal from the wafer is first boosted by a micropower transistor amplifier and then fed to an ultra low power voltage comparator. When the vibration signal has sufficient amplitude, a FET transistor switch is activated. Drawing only 6uA, the whole circuit is powered by a lithium coin battery, which should power the circuit for many years. Source: discovercircuits   (View)

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Electrodeless Water Level Monitor

Published:2012/9/5 20:43:00 Author:Ecco | Keyword: Electrodeless, Water Level , Monitor

This system operates much like a classic float switch but without any moving parts. The illustration shows how a system using two copper coils sealed inside a plastic pipe, can detect the level of water outside the pipe. Whenever the water level is lower than the upper coil, no signal is coupled between the coils. Once calibrated, this technique might also work on the outside of a plastic water tank. Source: discovercircuits   (View)

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1 LINE TELEPHONE LINE STATUS INDICATOR

Published:2012/9/5 20:42:00 Author:Ecco | Keyword: 1 LINE, TELEPHONE LINE , STATUS INDICATOR

This circuit is similar to the above circuit, but only monitors one phone line. Source: discovercircuits   (View)

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On/Off Latch Circuit 6

Published:2012/9/5 20:41:00 Author:Ecco | Keyword: On/Off Latch

Often you want to turn on and off power to a device with a single pushbutton switch. The circuit below performs this logic function with just a few tiny parts and can operate from DC supplies between +2v and 5v. It uses two inverters within a 6 pin SN74LVC2G14 device from Texas Instruments. Each press of the button toggles between the two on/off logic states. The logic output is connected to a PMV65XP p-channel FET from Philips. This component should be able to handle 2 amps of current Source: discovercircuits   (View)

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Low Voltage Latching Relay Driver

Published:2012/9/5 20:40:00 Author:Ecco | Keyword: Low Voltage, Latching, Relay , Driver

Using some small super capacitors, this circuit can latch and unlatch a mechanical relay with 10 amp contacts, from a small 3 volt power source. By using a latching relay, power can be controlled to a load with a tiny battery. Source: discovercircuits   (View)

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VOLTAGE TO FREQUENCY CONVERTER + 1uS LED PULSE DRIVER

Published:2012/9/5 20:39:00 Author:Ecco | Keyword: VOLTAGE TO FREQUENCY, CONVERTER , + 1uS , LED PULSE DRIVER

This circuit receives the signal from the above amplifier and launches powerful 1uS infrared light pulses from a low cost LED that are frequency modulated by the audio information. The 10KHz center frequency of the pulse stream is low enough so a standard infrared LED can emit ten times more light than conventional long pulse techniques. The circuit is described in more detail in the transmitter section of my Handbook of Optical Through the Air Communications. Source: discovercircuits   (View)

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DC Current Indicator 6

Published:2012/9/5 20:20:00 Author:Ecco | Keyword: DC Current, Indicator

The circuit below is a simple way to indicate when DC current is flowing through a wire. The circuit is designed so it will turn on a LED indicator light, whenever the voltage drop across a shunt resistor exceeds about 0.1 volts. The value of the resistor can be selected based on the desired current flow. Although I show a circuit for 12v operation, the circuit can be used over a wide range from 3v to perhaps 24v. Source: discovercircuits   (View)

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Double-key touching lamp switch circuit (3)

Published:2012/9/4 22:41:00 Author:Ecco | Keyword: Double-key , touching lamp switch

As shown in the figure, it is a double-key touching lamp switch with Darlington transistor, the feature of circuit is that touching tablet and 220V AC mains are isolated by power transformer T, it is relatively safer. The T can be 220V/9V, 5VA small power transformer; K should use ultra - small JZC-22F/2Z-09 power relay.   (View)

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Double-key touching lamp switch circuit (7)

Published:2012/9/4 22:34:00 Author:Ecco | Keyword: Double-key, touching lamp switch

As shown in the figure, it is a double-key touching lamp switch with two-wire system connection, and the left part of dashed in the figure is the general lighting circuit, the right part is the light switch, M1 is the touching tablet to turn on the light, M2 is the touching tablet to turn off the light. The load capacity of the circuit is mainly determined by the current capacity of VT3 and VD1 ~ VD4, the icon data load power is below 100W, and the load is suitable for incandescent bulbs, and the inductive load can not be used.   (View)

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Voice-control double light switch circuit (SK-IV)

Published:2012/9/4 21:39:00 Author:Ecco | Keyword: Voice-control , double light switch

The circuit uses SK-IV voice-control integrated circuit as the core component. Since the manifold requires three times of sound emitted by user continuously at a specific time to trigger the work, the circuit has a very high anti - interference performance. VS can use the 6V, 1/2W Zener diode; VTH1 , VTH2 should use 1A/400V small plastic Triac with small trigger current, such as MAC94A4 with control load being up to 100W; T is 220V/9V, 5VA small-quality power transformer. Other components have no special requirements.   (View)

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