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This is a very simple circuit which can be modified to the user's needs. Its operation is simple, when the input voltage is 0, the LED (LO). The LED turns off when the voltage increases to the level determined by R2. Voltage Monitor Circuit Diagram

I have just recently had solar pv installed, mainly to future proof my energy costs, I do not expect it to be like drilling for oil in my back garden, however the return looks to be encouraging. The install gives you another single unit meter, from this you will see the total amount the panels produce, but that is about it. I wanted to know how much the production was as it was happening, I discovered the light blinks on the front of the meter will flash 1000 times for each kWh of electricity which passes through. The rate of the flashing of the LED tells you how much power is currently passing through the meter. [ ]

Idealy if you have a combustion heater in your home, there should be some means of monitoring the air quality. This is where the Air Quality Monitor comes in, it measures both carbon dioxide and carbon monoxide levels, and displays the results on LED bargraphs. If the concentration of either of these gases rises above a preset level, a loud alarm will sound, which means that you should turn off the heater and open the room up to fresh air. Each bargraph comprises eight LEDs that light invidually to show eight distinct levels. In between values are displaed by lighting two adjacent LEDs. This gives a total of 15 levels that can be displayed. The four lower LEDs are green, followed by two orange and then two red LEDs. An automatic dimming circuit ensures that the LED displays are not too bright at night. In addition, the alarm sounds if any of the top three LEDs light in either display. There are three alarm levels: Main alarm sounds if the top LED lights. This consists of a 64ms-long 4...

The BVM1 is an ultra low power ten LED battery voltmeter circuit that is optimized for monitoring solar-charged 12V battery systems. The circuit features an expanded meter scale that displays ten color-coded voltage steps from 10.5V to 15.0V. Power is conserved by only turning on the appropriate LED for a short but bright flash once every 1.25 seconds. The LED display can be turned on continuously (no blinking) by turning the Calibrate switch on, more battery power is consumed in this mode. BVM1-12 Volt Battery Voltage Monitor With Parts List  The BVM1 also includes a battery low voltage beeper that warns when the battery voltage drops below a preset voltage. The beeper can be turned on and off with the L.V. Beep Activate switch. The BVM1 is protected against reverse voltage connection and is fused for safety. The design goals of this circuit were efficiency, simplicity, reliability and the use of field replaceable parts. The BVM1 circuit has been designed to work in conjunction w...

This circuit is used to monitor the battery voltage to display a dual-colored LED status of the battery to. If the LED “green”battery voltage exceeds 11.9 volts. If the yellow LED , battery voltage 11.9 to 11.5 volts. If the LED is “red” If the battery voltage below 11.5 volts. You can of course change the trigger points by the trimmer resistors and / or changing the value of the resistors in the divider.  .  Simple Car Battery Voltage Monitor Circuit Diagram . A dual op amp is used as a comparator. The green LED on the board, until the voltage exceeds 11.5 volts. The red LED illuminates when the voltage falls below 11.9 volts to the circuit. Therefore, in the 11.9 to 11.5 volts, both LEDs are on, producing a slightly yellow color. When the voltage falls below 11.5 V, the green LED , and now only the red LED flashes to indicate low voltage. Parts List R1=1K2 R2-3-4=680R R5=15K R6=10K R7-8-9-10=1K IC1=LM324 D1=5V6 /0.5W Zener D2-3-4-5=LED RV1=10K trimmer  Is recommend...

Used ICs: LD7552BS – AM9945N-T1-PF – OZ9938GN - STP9NK65ZFP[FET] The LCD monitor will contain a main board, a power board and two key boards which house the flat panel control logic, brightness control logic and DDC. The power board will provide AC to DC Inverter voltage to drive the backlight of panel and the main board chips each voltage. SMPS and Back-light section circuit diagram [Click on the circuit diagrams to magnify]

Treatment LCD Monitor. At this time computer use familiar and already widely used either for work or entertainment. And of course when talking about computers it will not be far away with a device called a monitor. And today use CRT monitors have started to decrease with the LCD Monitor that despite having a price that is quite expensive but have many advantages than conventional CRT monitors. Here are a few advantages of LCD monitor is a stylish design, flat screen and a brighter color than convex or crt monitor screen, while also LCD Monitors have many advantages among which have a high resolution so that it can help many people especially those working Visual design field. There are some special treatment for LCD monitors in this case is for the treatment of LCD monitors, the following are some steps steps: Use the LCD as needed, Do not use if you do not need so-necessary and do not use it 24 hours nonstop jedanya have no time for any electronic item there during his lifetime (Lifet...

The circuit in the diagram was originally designed to monitor an oscillator, but can also be used as a general-purpose level indicator for a.c. signals. It is based on a quadruple IC containing four NAND gates. Only three of the gates are used, making the fourth free for other purposes. All the gates have a Schmitt trigger input. When a 5 V supply is used, the Type 74HC132 is recommended; for higher voltage, a Type 4093. Note, however, that these two ICs have different pinouts. In the diagram, the differing pins of a 4093 are shown in brackets. The signal to be monitored is applied to the input of the first gate via capacitor C1. Resistor R2, in conjunction with the protection diode in the IC, guards the input to high voltages. In the absence of a signal, resistor R1 holds the input high so that the output of the gate is low. When a signal of sufficient strength is received, the input of the gate goes low during the negative half cycle of the signal, so that the output of the gate goes...

Walkie-talkies (also known as handheld or PMR, Personal Mobile Radio) can be bought at low prices even from department stores, and they can be operated without a licence in many countries. Considering the low cost, such a set would be very suitable for use as a wireless baby monitor, with the addition of several external components. These are connected to the jack sockets for an external loudspeaker/microphone and an external PTT (Push-To-Talk) switch, which are often found on these devices. Project Image : Wireless Baby Monitor Project Image The walkie-talkie with the extra electronics and microphone is placed in the baby’s room. When the PTT switch on the other walkie-talkie is actuated for about a second the ‘baby’ walkie-talkie produces a series of tones, which the external electronics can detect. This then activates its own PTT switch for about 5 seconds, so it switches over to transmit. During this time the other device can hear what the external microphone picks up. C...

This is a Simple Car Battery Monitor Circuit Diagram. A close call on the road can really focus your mind on the importance of having a battery monitor in a car. I had been enjoying a pleasant week of travelling around the countryside at a leisurely pace and taking in the beautiful scenery each day. It wasn't until the final day, with the big rush to return home, that I had to drive at night.My home is deep in the country and on the road I was travelling the closest petrol station may be 80km away. I was travelling through an area that is full of open-cut coal mines and large heavily loaded semi-trailers constantly pound the roads, travelling at quite high speeds. It was around 8pm at night and everything was very dark no street lights or house lights anywhere. Just as I was going up a hill, the lights began to dim and the engine coughed. A large semi-trailer loomed in the rear-vision mirror as I pushed the clutch in and tried to restart. My speed was falling rapidly and my lights ...

The circuit described below monitors your car's  brake lights, and indicates by a light emiting diode  whether they both function correctly. In that sense, it can save you money by preventing your being fined for driving with defective brake lights, and it also leads to increasing road safety. Circuit diagram : Brake Lights Monitor Circuit Diagram The monitor depends inevitably on the voltage drop across the supply lines to the two lamps. For the circuit to work correctly, that drop needs to be greater than 0.6 V. If this is not so, the drop must be increased by adding a 5 V diode in series with each lamp. Transistor Ti and T2 in figure 1 form a  Schmitt trigger, which reacts to the voltage drop across the supply lines to the two brake lights. This reaction manifests itself in Di lighting via T3. If  one of the brake lights is faulty, the switch-on cur- rent drawn by the other lamp will cause Di to light  briefly when the brake pedal is pressed. If both  brake lights are defec...

The circuit described below monitors your car's brake lights, and indicates by a light emiting diode 12V whether they both function correctly. In that sense, it can save you money by preventing your being fined for driving with defective brake lights, and it also leads to increasing road safety. Car's Brake Lights Monitor Circuit Diagram : The monitor depends inevitably on the voltage drop across the supply lines to the two lamps. For the circuit to work correctly, that drop needs to be greater  than 0.6 V. If this is not so, the drop must be in- creased by adding a 5 V diode in series with each  lamp. Transistor Ti and T2 in figure 1 form a  Schmitt trigger, which reacts to the voltage drop  across the supply lines to the two brake lights. This  reaction manifests itself in Di lighting via T3. If  one of the brake lights is faulty, the switch-on cur- rent drawn by the other lamp will cause Di to light  briefly when the brake pedal is pressed. If both  brake lights are defe...

Rechargeable batteries of 6V and 12V are used in a large number of applications. It is imperative that these are maintained properly to get maximum life out of them. Further, their permissible number of charge-discharge cycles must be fully utilised. Here is a circuit that gives a visual as well as an audible alarm if the battery voltage is higher or lower than acceptable limits, so that corrective action can be taken. Circuit and working As shown in Fig. 1, the circuit is built around dual-operational amplifier LM358 (IC1), hex inverting Schmitt trigger 74HC14 (IC2) and a few other components. The circuit can be divided into two parts—the input unit built around two operational amplifiers (op amps) in IC1 working as comparators, and audio alarm unit built around two RC oscillators and a transistor. Voltage from the battery under test (BUT) is applied to connector CON1. It is divided by five by R1 and R2 for comparison with the threshold levels. the power supply of the circuit is limit...