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3 Digits Digital Volt Meter with PIC16F676 - This is simple 3-digits digital volt
meter.PIC16F676 used to read analog signal(voltage) and display the value on 3-digits
7-segment. You can apply similar principles to measure DC current with parallel R
shunt.
.(circuit design added 11/08) |
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3 Level Audio Power Indicator - Battery-operated3 LED display that connect it to
loudspeaker output (added 04/02) |
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3-Digit DVM Voltmeter - Uses 3161, CA3162 ICs
.(design added 11/08) |
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3-digit Volt / Amper Meter - Even if the digital multimeters have dominated in a
lot of applications, in the measurement, exist the need for existence of instruments
of clue in various appliances, voltage and current, as in power supply or elsewhere.
The circuits that give make this precisely the work, measure the voltage in terminal a
circuit and the current that passes in his. The circuit does not present particular
difficulties for somebody that has a small experience. The two circuits are the
himself, with a small difference only in their input, when they have they measure
voltage or current and in connection that concern decimal point.
.(circuit design
added 11/08) |
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9v Battery Voltage Monitor - This circuit turns on a LED whenever the voltage of a
standard 9v battery connected to the circuit drops below 7.2 volts. It uses a
LTC1440 comparator, which also contains a 1.18v reference diode. In standby
mode, the circuit draws only 4uA. (added 7/06)
.(designed by David A. Johnson) |
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AC Line Under/Over Voltage Alarm - Power lines, which deviate much beyond normal
voltages can damage expensive electronic equipment. The circuit below sounds an
alarm whenever the line voltage is higher or lower than normal. I set the alarm
limits at about +-15% from standard levels. The circuit rectifies and filters
the power line signal. I set the resistor values, so the DC voltage produced is
close to 1% of the RMS value of the line. Thus, a 120vac line would yield about
1.2v DC. That voltage is fed to a pair of voltage comparators. The outputs
of the comparators decide if the sampled voltage is above, below or acceptable. ....
.(designed by David A. Johnson) |
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AC Voltmeters and ammeters - Electronic circuit design (added 02/05) |
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Acceptable Voltage Indictor - I have used this circuit many times in custom test
fixtures where a simple go-no go indication was needed. The circuit can also be
used to adjust a particular voltage be within specific high or low limits. The
three LEDs will indicate if the voltage is high, low or OK. When connected to
other converters, such as a frequency to voltage converter, a current to voltage
converter or a power to voltage meter, it could provide a quick indication of a proper
level.
.(designed by David A. Johnson) |
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AN557: Four Channel Digital Voltmeter with Display and Keyboard - Microchip
Application Note Published 27-May-05 (app note added 2/06) |
|
AN779: Using the Microchip TC54 Voltage Detector - Microchip Application Note
Published 12-Nov-02 (app note added 2/06) |
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Analog Milliamp Meter Used as Voltmeter - This ring generator will ring a
telephone once every 10 seconds. The interval between rings can be lengned or
shortened by varying value of 1 Meg resistor. The 70 volt/ 30 Hz ring
voltage is produced from 120 volt side of a small 12.6 VAC power transformer
(Radio Shack 273-1365). Both capacitors connected across transformer windings
are non-polarized / 100 volts. Circuit draws....(added 6/06) |
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AVR Digital Voltmeter - Most electronics hobbyists these days find a digital
voltmeter indispensable. Indeed, having more than one is a positive advantage! This
little project with six voltmeters in one inexpensive box therefore has some very
useful features for the hobbyist. The unit is quite inexpensive, two ICs and a couple
of transistors. One of the ICs is an AT90S4433 AVR..(electronic circuit added 4/05) |
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Ballantine 300 AC Voltmeter manual w/schematic - (added 07/07/07) |
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Battery Monitor Draws 8 ΅or Less - 04/13/95 EDN-Design Ideas: (design idea
added 3/03) |
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Battery Monitor Draws 8 ΅or Less - 04/13/95 EDN-Design Ideas: The battery
monitor in Fig 1 nominally draws 5 ΅A during normal operation and flashes an alarm
indicator when the battery voltage drops below a critical value. The alarm-state
current depends on the desired indicator brightness, but you can easily make the
current average less than 500 ΅A. This monitor was developed as a change-battery
warning.....(design idea added 3/03) |
|
Battery Monitor Emulates Auto Dashboard - 07/03/97 EDN-Design Ideas: When
you use battery-powered scientific-recording equipment, you must know the state of the
battery, because an unnoticed battery run-down can lead to loss of data. Several types
of warning indicators are available, but all have their drawbacks. Moving-coil
indicators, test terminals, and digital flags, for example,.....(design idea added
3/03) |
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Car Voltage Gauge - The Car Voltage Gauge is based on 3 parts. The input circuit
is an Analog to Digital Converter (IC2 CA3162E). The purpose of this chip is to sample
an analog voltage and convert it to a decimal value which is read by a Display/Decoder
Driver (IC1 CA3161E). This chip will turn each seven segment display
.(added 6/07) |
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Circuit Detects and Disconnects OverVoltages - 04/25/96 EDN-Design Ideas:
(design idea added 3/03) |
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Circuit Detects Current Pulses - 01/06/94 EDN-Design Ideas: The pulse
detector provides a visible indication of positive and negative current pulses. The
pulses amplitudes can vary from20 to150 mA. The pulses durations can range from10 to40
msec, and their repetition rate can span40 to180 pulses/minute.....(design idea added
3/03) |
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Circuit Detects DC Ringing - 08/17/00 EDN-Design Ideas: (design idea added
2/06) |
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Circuit detects first event - 05/03/01 EDN-Design Ideas: (design idea added
2/06) |
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Circuit detects reset source - 04/27/00 EDN-Design Ideas:.....(design idea added
2/06) |
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Circuit Detects total OnTime - 02/04/99 EDN-Design Ideas: The circuit in
Figure 1 provides a voltage that is directly proportional to the sum of the total
on-times for a number of positive pulses that occur during the interval between sample
signals. When a positive pulse.....(design idea added 8/03) |
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Circuit Detects Voltage over Ranges - 10/10/96 EDN-Design Ideas: (design
idea added 3/03) |
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Circuit Disconnects Load from Battery - 03/14/96 EDN-Design Ideas: (design
idea added 03/03/03) |
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Circuit Provides 15V 7Bus Termination - 09/14/95 EDN-Design Ideas: (design
idea added 3/03) |
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Circuit safely applies Power to ICs - 11/22/01 EDN-Design Ideas: Supervisory
circuits normally monitor a microprocessor's supply voltage, asserting reset to the IC
during power-up, power-down, and brownout. In this way, the circuit ensures that the
supply voltage is.....(design idea added 1/05) |
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Clamping Circuit Dissipates Minimal Power - 03/30/00 EDN-Design Ideas: / PDF
contains multiple circuits, scroll to find the one of interest / This circuits is a
quasi-linear regulator.....(design idea added 5/02) |
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Cockcroft Walton Diode Voltage Multipliers - this document describing some basic
voltage multiplier circuit topologies, PDF file (added 5/02) |
|
Comparator Detects Failed Telecomm Supplies - 06/22/00 EDN-Design Ideas:
/Detects when telecomm power supplys48V output drops below its nominal value, uses an
isolated comparator to monitor two48V telecomm supplies (of either polarity)/ PDF
contains multiple circuits scroll to find the one of interest.....(design idea added
5/03) |
|
Comparator detects position of peaks and valleys in a waveform - 05/24/07 EDN-Design
Ideas: Simple comparator circuit locates peaks and valleys of a waveform in
time.....(design idea added 9/08) |
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Contactless AC Mains Voltage Detector - (electronic Circuit / Schematic added
10/04) |
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DC Power Supply (Randy Linscott) - I didn't realize till the other day that I have
never shown a circuit for a standard power supply. Shown below is a supply that will
use any of the LM78XX series of voltage regulators. The transformer in the circuit
will vary depending on which regulator you use. For voltages from 5 to 12 use a
transformer with output of 18vac. With voltages from 15 to 24....(added 08/08/08) |
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Digital LED Voltmeter - Measures voltages up to 199.9V with 0.1V resolution.
(circuit added 8/06) |
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Digital Mains Voltage Indicator - (electronic Circuit / Schematic added 10/04) |
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Digital Volt and Amp Meter with Temperature Control -
.(design added 08/08) |
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Digital Volt Meter with Video Output - (schematic / circuit design added 08/05) |
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Digital Voltmeter -
.(electronic schematic added 08/08) |
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Expanded Scale Battery Volt Meter - This circuit is used to measure the voltage on
a 12V (nominal) lead acid rechargeable battery system. It was specifically designed
for use in solar powered systems, but is general enough that it can be used for
automotive or other 12V systems. Lead acid batteries normally spend their working
lifetime in the voltage range of 11-15 Volts. This meter circuit....(added 10/05) |
|
Expanded Scale Indicator Revisited - 08/08/02 EDN-Design Ideas: The
visualization aid that a previous Design Idea describes allows only the expansion of
the upper end of the scale (Reference 1). But what can you do if, according to your
project requirements, you need to expand the middle region of the scale? Figure 1a
illustrates the challenge. A voltmeter comprises a 100-΅A dc meter and a series
resistor.....(design idea added 1/05) |
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Expanded Scale Voltmeter uses Just Two Parts - 01/20/94 EDN-Design Ideas:
The expanded voltmeter doesn't require trimpots to obtain usable accuracy or require
the tedious selection of Zener diodes. This circuit consists of only two parts and a5V
meter. The circuit is completely linear and requires no calibration except the rare
mechanical zeroing of the meter. By using.....(design idea added 6/02) |
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Four Channel Digital Voltmeter with Display and Keyboard - Microchip Application
Note Published 27-May-05 (app note added 2/06) |
|
High Impedance Voltmeter - (schematic / circuit added 2/07) |
|
High-impedance voltmeter - An ideal voltmeter has infinite input impedance,
meaning that it draws zero current from the circuit under test. This way, there will
be no "impact" on the circuit as the voltage is being measured. The more current a
voltmeter draws from the circuit under test, the more the measured voltage will "sag"
under the loading effect of the meter, like a tire-pressure gauge...(schematic added
6/07) |
|
Hippasian nonlinear VFC stretches dynamic range - 02/19/09 EDN-Design Ideas: ,
A voltage-to-frequency converter uses square roots to extend dynamic range by orders
of magnitude.....(design idea added 08/09) |
|
HOTCHEK - The HOTCHEK is a compact expanded scale voltmeter designed to check the
receiver battery pack. Its very small size makes it great as onboard voltage monitor
or it can be used as a "pocket meter," replacing those old fashioned bulky meters. A
0.3A load can be placed across the batteries with a push of a button allowing the true
state of the pack to be tested (added 6/07) |
|
How to Use the MAXQ2000 as a Voltmeter - Maxim App Note 4194 -- 3/24/2008 --
(app note add 5/08) |
|
Latching Regulator Prevents Deep Discharge - 03/16/95 EDN-Design Ideas:
(design idea added 03/03/03) |
|
LB-48: Linear Brief 48 Simple Voltmeter Monitors TTL Supplies - National
Semiconductor Application Note (app note added 2/06) |
|
LED display digital Voltmeter - This digital voltmeter is ideal to use for
measuring the output voltage of your DC power supply. It includes a 3.5-digit LED
display with a negative voltage indicator. It measures DC voltages from 0 to 199.9V
with a resolution of 0.1V. The voltmeter is based on single ICL7107 chip and may be
fitted on a small 3cm x 7cm ...(electronic design added 6/07) |
|
Low Battery Voltage Flasher - This circuit is designed to monitor two alkaline
cells (3v) that from 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. In the off state the circuit draws only 1uA, while in the active flashing state
it draws 20uA. Published in EDN, Jan 2, 1997
.(designed by David A. Johnson) |
|
Low Power LED Voltmeter - This is a low power voltmeter circuit that can be used
with alternative energy systems that run on 12 and 24 volt batteries. The voltmeter is
an expanded scale type that indicates small voltage steps over the 10 to 16 volt range
for 12 volt batteries and over the 22 to 32 volt(electronic diagram added 6/03) |
|
Low Voltage Alarm (Aaron Cake) - NE555 Low Voltage Battery Disconnect Circuit
(added 5/02) |
|
Mains Voltage Indicator - The solidstate voltmeter circuit described here
indicates the mains voltage with a resolution that is comparable to that of a
general-purpose analogue voltmeter. The status of the mains voltage is available in
the form of an LED bar graph.....(electronic Circuit / Schematic added 10/04) |
|
Maximum Voltage Sorter uses Analog Multiplexers - 09/29/94 EDN-Design Ideas:
The voltage-sorting circuit in Fig 1 continuously finds the maximum of eight input
voltages and the corresponding binary address with the aid of two analog multiplexers,
IC1 and IC2. The circuit compares each input sequentially with the current maximum
voltage and updates the maximum voltage and address when it finds a new
maximum.....(design idea added 3/03) |
|
MicroController functions as voltmeter - 05/10/07 EDN-Design Ideas: PIC
microcontroller and FETs enable a four-digit voltmeter.....(design idea added 9/08) |
|
Microprocessor supervisor and regulator form in range Voltage monitor - 06/10/04
EDN-Design Ideas: Low-cost microprocessor supervisors reset controllers when
power-supply voltages fall below given levels. As added protection, you can also reset
the microcontroller when the power supply is too high by combining a low-cost
shunt-voltage regulator with a supervisor that has a manual reset input. A simple
overvoltage/undervoltage-protection.....(design idea added 1/05) |
|
OpAmp Rectifier Signals Input State - 07/21/94 EDN-Design Ideas: The op-amp
rectifier in Fig 1 operates from a single supply and provides a logic output and an
LED that indicate the state of the input voltage. The input-state indications are
handy for calibration. Because the circuit operates from a single supply, the 2.5V
reference determines the level around which the circuit rectifies input
waveforms.....(design idea added 3/03) |
|
Serial Voltmeter using the PIC16C71 - Building a serial voltage meter to measure
from 0 to 5 volts DC is actually pretty easy. Using MeLabs PicBasic, and Microsoft's
Visual Basic Version 5 Pro. You need Visual Basic Pro version because you will have to
use Basic's MSComm control. This control is not available in the Visual Basic 5
"Learning" Edition. The PIC16C71 simplifies the task even more by having a built in
A/D converter. Pins 17,18,1,2 are the analog inputs AIN0,AIN1,AIN2,AIN3 respectively.
.(electronic schematic added 11/08) |
|
Simple Circuit Detects Voltage over Ranges - 10/10/96 EDN-Design Ideas:
(design idea added 3/03) |
|
Simple Circuit Disconnects Load from Battery - 03/14/96 EDN-Design Ideas:
(design idea added 03/03/03) |
|
Simple Voltmeter Monitors TTL Supplies - National Semiconductor Application Note
(app note added 2/06) |
|
Small Detector Coils with Ferrite Cores for my PI Detectors -
.(electronic
schematic added 12/08) |
|
Solid State Relay Saves Battery's Life - 09/01/94 EDN-Design Ideas: The
circuit in Fig 1 uses a low-resistance p-channel FET, Q4, to disconnect a load from
the battery when the battery's voltage drops below a certain value. After you
disconnect the circuit, it remains off until you remove and replace the
battery.....(design idea added 5/02) |
|
Status Indicator Flags Five Discharge States - 01/20/94 EDN-Design Ideas:
The circuit actually indicates five conditions of the battery. A steady glow assures
the user that the battery is strong and healthy. A2-Hz brief flicker off indicates
that the battery is starting to show age. A more insistent,50%,5-Hz flashing is a
warning to have a spare battery on hand. A brief flicker.....(design idea added 3/03) |
|
Supervisory IC Makes Simple Line Monitor - 03/01/96 EDN-Design Ideas:
(design idea added 03/03/03) |
|
Talking Voltmeter - Ever needed to measure a voltage without taking your eye off
something? If so, then this is the project for you! The Orton Talking Voltmeter takes
a voltage measurement in the range 0-5 Volts and then reads it out to you to two
decimal places (i.e. to 10mV resolution). The design illustrates the use of the 10 bit
ADC in the PIC, .....(added 04/04/04) |
|
Using the Microchip TC54 Voltage Detector - Microchip Application Note Published
12-Nov-02 (app note added 2/06) |
|
Volt Meter with Video Output - (schematic / circuit design added 08/05) |
|
Voltmeter Monitors TTL Supplies - National Semiconductor Application Note
(app note added 2/06) |
