Norman Lathrop Enterprises | Norman Lathrop Enterprises
Index To How To Do It Information
Lathrop Report On Newspaper Indexes
A profile of Norman Lathrop Enterprises
Last Updated
  Index Home  |   A-Z Subject Heading Guide    |   Keyword Search  |   Union List 

Detailed entries for one subject from the INDEX TO HOW TO DO IT INFORMATION.
Click on a see also (sa) or tracing (xx) to view detailed entries about a related subject.
The entries are in alphabetical order by magazine name and then in chronological sequence.
To obtain a copy of any magazine article contact your local public library or the publisher.


Power supply voltage monitor uses a tricolor LED display to indicate whether the voltage is above, below or within acceptable limits. Can monitor voltages between 5 and 15V.
AUDIO AMATEUR 1/1987 [Jan 1987] (v.18#1) pg. 47

An AC power-line monitor displays the voltage on a 3.5-digit LED.
AUDIO ELECTRONICS 4/2000 [Jul 2000] (v.31#4) pg. 20

Build an RS-232C breakout box, a decade voltage-level indicator, and a terminal simulator. These diagnostic tools will help you make working serial connections.
BYTE Apr 1983 (v.8#4) pg. 28
Correction BYTE Aug 1983 (v.8#8) pg. 432

A multiple test-point monitor measures voltage at a number of circuit points simultaneously.
COMPUTERS & ELECTRONICS Sep 1983 (v.21#9) pg. 76

How to add a "fuel gauge" to your Radio Shack Model 100 lap computer to give you a visual indication of the state of the batteries in use. The "fuel gauge" is basically a voltmeter with a conversion program that correlates the battery voltage to the ampere-hour capacity of the batteries.
CQ. THE RADIO AMATEUR'S JOURNAL Apr 1987 (v.43#4) pg. 18

AC powerline monitor displays either the voltage level or relative noise level on the LED display. Est. cost: $45.

Voltage tester glows red when connected to 5- to 400-volts, either AC or DC. Also shows polarity of DC voltage.
ELECTRONICS ILLUSTRATED Nov 1970 (v.13#6) pg. 87

Circuit will indicate when a voltage level either falls below or rises above a particular value. Can be set to trigger on whatever voltage you want.
ELECTRONICS NOW Sep 1993 (v.64#9) pg. 8

Voltage comparator circuit turns on an LED whenever an input voltage falls below a reference voltage. Uses the LM339 IC.
ELECTRONICS NOW Jul 1995 (v.66#7) pg. 8

Over/under voltage protector monitors AC line voltage and disconnects the load if the input voltage goes below 95 volts or above 130 volts. Brief power outages (1/10 second) won't disrupt service. Est. cost: $40 (kit).
ELECTRONICS NOW Sep 1995 (v.66#9) pg. 39

Circuit used to detect an increase in voltage. A relay pulls in whenever the voltage exceeds about 17 volts DC.
ELECTRONICS NOW Feb 1998 (v.69#2) pg. 6

AC line voltage monitor causes a lamp to blink, until reset, should line voltage drop below 100 volts.
ELECTRONICS WORLD Jan 1969 (v.81#1) pg. 85

Voltage tracker can monitor a voltage unattended, remember the direction of voltage fluctuation, or the arrival or non-arrival of a pulse. Est. cost: $25.
ELEMENTARY ELECTRONICS Nov-Dec 1966 (v.3#2) pg. 49

Power supply balance indicator. Three LED's indicate when the positive and negative levels of a split power supply are within 1% of each other.
HANDS-ON ELECTRONICS Jan-Feb 1986 (v.3#1) pg. 96

Circuit turns on an LED whenever a battery voltage drops below a predetermined level.
HANDS-ON ELECTRONICS Nov 1986 (v.3#6) pg. 28

Automobile battery voltage monitor circuit lights an LED if voltage falls below 11 volts.
HANDS-ON ELECTRONICS Apr 1987 (v.4#4) pg. 93

Battery monitor circuit lets you know when battery voltage falls below the preset limit.
HANDS-ON ELECTRONICS Nov 1987 (v.4#11) pg. 93

AC-line disturbance monitor detects noise and high/low voltages.
HANDS-ON ELECTRONICS Dec 1987 (v.4#12) pg. 39

Build a 12-volt battery-voltage monitor to determine battery status under normal equipment load.
HANDS-ON ELECTRONICS Jul 1988 (v.5#7) pg. 69

Using op-amp comparator circuit chips to detect and measure real-world conditions. Circuits for monitoring temperature, light level, voltage, etc.
HANDS-ON ELECTRONICS Aug 1988 (v.5#8) pg. 62

Build the low-battery alarm. Simple circuit monitors the voltage of back-up batteries in clocks, timers, etc. Sounds an alarm when voltage drops to 5 volts.
HANDS-ON ELECTRONICS Aug 1988 (v.5#8) pg. 70

Circuit for an inexpensive dc supply voltage monitor that sounds an audible warning if voltage drops below a preset level.
MODERN ELECTRONICS [1] Feb 1978 (v.1#1) pg. 73

Circuit which can be used to monitor voltage output of a variable voltage power supply. An LED will light up at preset voltages (such as 5 and 12 volts) when your output reaches that level.
MODERN ELECTRONICS [1] Sep 1978 (v.1#7) pg. 6

Experimenting with the analog comparator, a special circuit incorporating the operational amplifier. Circuits include (1) an adjustable light-dark detector, (2) adjustable-threshold temperature-controlled relay, (3) a sine- to square-wave converter, and (4) a peak-voltage detector.
MODERN ELECTRONICS [2] Feb 1985 (v.1#5) pg. 62

Using voltage comparators. A hands-on look at the popular and readily available LM339 which features four separate comparators in a single 14-pin DIP. Used in circuits to convert from analog-to-digital, monitor voltage levels, convert from one logic family to another, etc.
MODERN ELECTRONICS [2] May 1985 (v.1#8) pg. 36
Correction MODERN ELECTRONICS [2] Jul 1985 (v.2#1) pg. 4
Correction MODERN ELECTRONICS [2] Nov 1985 (v.2#5) pg. 91

R/C aircraft crash saver. An accurate battery status indicator for on-board radio-control gear ensures availability of sufficient power for takeoff and landing of costly model airplanes. Uses LEDs to show if Ni-Cd battery has 4.8-, 4.6-, 4.4-, or 4.2-volts available.
MODERN ELECTRONICS [2] Dec 1987 (v.4#12) pg. 56
Correction MODERN ELECTRONICS [2] Feb 1988 (v.5#2) pg. 7
Correction MODERN ELECTRONICS [2] Jul 1988 (v.5#7) pg. 5

Visual regulator monitor. Separate circuits with LEDs alert you to loss of regulation, overcurrent and thermal problems caused by regulator ICs in power supplies.
MODERN ELECTRONICS [2] Oct 1988 (v.5#10) pg. 52

Automotive battery/charging system analyzer. Simple, low-cost circuit uses a series of LEDs to report on vehicle electrical-system status.
MODERN ELECTRONICS [2] Mar 1989 (v.6#3) pg. 40

AC line monitor alerts you when ac line voltage and frequency conditions are detrimental to the health of your computer and other sensitive electrical equipment.
MODERN ELECTRONICS [2] Jul 1990 (v.7#7) pg. 14

Battery monitor. An easy to read voltmeter uses green, yellow and red LEDs to indicate the state of charge of a 12-volt battery. Est. cost: $26.
MOTHER EARTH NEWS #75 May-Jun 1982 pg. 134
Correction MOTHER EARTH NEWS #76 Jul-Aug 1982 pg. 176

Voltage monitor for a 12-volt supply will turn on a lamp if the voltage drops below a certain level. Est. cost: $6.
POPULAR ELECTRONICS [1] Nov 1971 (v.35#5) pg. 63

Electronic circuit switches off a 12-volt battery if its output drops below 9 volts.
POPULAR ELECTRONICS [1] Jan 1974 (v.5#1) pg. 26

Circuit for a 115- to 125-volt power line monitor.
POPULAR ELECTRONICS [1] Apr 1974 (v.5#4) pg. 24

Circuit with zener-controlled relay trips alarm if the voltages exceed the zener point.
POPULAR ELECTRONICS [1] Nov 1974 (v.6#5) pg. 17

A look at the voltage comparator and its use in logic control and instrumentation equipment. Application circuits for a reference supply, a 100-kHz multivibrator and oscillator, and a voltage controlled oscillator.
POPULAR ELECTRONICS [1] Jun 1975 (v.7#6) pg. 63

Circuit for a wide range voltage probe. Can indicate the presence of any voltage from 1.5 to 150 volts ac or dc.
POPULAR ELECTRONICS [1] Aug 1976 (v.10#2) pg. 75

Circuit for a 117-volt ac line monitor.
POPULAR ELECTRONICS [1] Dec 1976 (v.10#6) pg. 28

Uses for the multiple integrated circuit LM339, a quad comparator. Containing four independent voltage comparators, it is used in circuits for (1) a voltage-controlled oscillator, (2) limit comparator and (3) limit comparator operated as a programmable light meter.
POPULAR ELECTRONICS [1] Jan 1977 (v.11#1) pg. 94

DC low-voltage monitoring circuit turns on an LED if voltage drops below a preset level.
POPULAR ELECTRONICS [1] Sep 1977 (v.12#3) pg. 92

The analog comparator. A circuit which compares an input voltage to a reference voltage and changes the state of its output only when the input exceeds the reference voltage. Several applications reviewed.
POPULAR ELECTRONICS [1] May 1979 (v.15#5) pg. 77
Added Info POPULAR ELECTRONICS [1] Aug 1979 (v.16#2) pg. 6

The digital comparator (magnitude comparator). Digital counterpart of the analog comparator discussed in the May 1979 issue.
POPULAR ELECTRONICS [1] Jun 1979 (v.15#6) pg. 81

Low voltage indicator circuit for batteries. Est. cost: $2.
POPULAR ELECTRONICS [1] Oct 1979 (v.16#4) pg. 85
Correction POPULAR ELECTRONICS [1] Dec 1979 (v.16#6) pg. 6

CMOS guardian will indicate if any 117-volt ac line-operated device has been switched on. Use it to detect unauthorized use of electrical devices. Does not sound an alarm or flash any lights.
POPULAR ELECTRONICS [1] Feb 1980 (v.17#2) pg. 96

An early-warning car battery-drain indicator replaces the standard "idiot" light with a visual-audible monitor which indicates low, normal and high voltage conditions. Est. Cost: $28.
POPULAR ELECTRONICS [1] Dec 1981 (v.19#12) pg. 69

Battery monitor circuit contains four LED's that are set to switch on if the supply voltage falls below any of the preset thresholds.
POPULAR ELECTRONICS [2] Apr 1989 (v.6#4) pg. 24

Simple metering circuit for monitoring voltages that don't vary too much (such as a car battery).
POPULAR ELECTRONICS [2] Jun 1989 (v.6#6) pg. 22

Digital electronics course. A close look at comparisons. Fundamental course in design and operation of comparators (a special op-amp used to compare the voltage levels presented to its two inputs).
POPULAR ELECTRONICS [2] Feb 1990 (v.7#2) pg. 69

Digital electronics course. Binary comparitors. How error and parity checking and other computer functions are implemented.
POPULAR ELECTRONICS [2] Jan 1991 (v.8#1) pg. 72

LED indicator circuits for all occasions. (1) AC pilot light. (2) DC pilot light. (3) Polarity indicator. (4) 5-volt voltage-level indicator. (5) Oscillator-driven flasher. (6) Decoder converts audio CW code into visual dots and dashes.
POPULAR ELECTRONICS [2] Oct 1991 (v.8#10) pg. 82

Voltage-level indicator circuit will indicate three different pre-set input voltage levels.
POPULAR ELECTRONICS [2] Sep 1992 (v.9#9) pg. 70

Adjustable voltage monitor can be used to check whether the voltage in a circuit remains within a given range.
POPULAR ELECTRONICS [2] Sep 1992 (v.9#9) pg. 71

Voltage monitor and detector circuits. (1) Glitch detector monitors a DC-voltage for a change (glitch) which can cause problems in a computer. (2) AC noise detector. (3) AC power-failure monitor checks for voltage glitches or failures.
POPULAR ELECTRONICS [2] Oct 1994 (v.11#10) pg. 82

Op-amp applications. (1) CMOS-interface driver, (2) dual-voltage supply, (3) AC amplifier, (4) adjustable comparator, (5) dual-voltage comparator, (6) four-level voltage detector, and (7) voltage window.
POPULAR ELECTRONICS [2] Oct 1996 (v.13#10) pg. 68

Build an AC line-voltage monitor that uses LEDs to indicate the voltage level in seven steps from 100 to 132 volts. Est. cost: $11 (kit).
POPULAR ELECTRONICS [2] Mar 1997 (v.14#3) pg. 52

Simple op-amp application circuits. (1) Fixed voltage reference. (2) Light-operated sensor. (3) Alarm sensor. (4) Voltage-level sensor. (5) Peak-voltage detector and hold. (6) DC motor driver and reverser. (7) Simple timer circuit to delay relay operation for up to 30 seconds.
POPULAR ELECTRONICS [2] Nov 1997 (v.14#11) pg. 62

AC power-line voltage monitor is designed to detect power outages, sags, surges, spikes, and large harmonic distortion. Est. cost: $50.
POPULAR ELECTRONICS [2] Apr 1998 (v.15#4) pg. 31
Correction POPULAR ELECTRONICS [2] Aug 1998 (v.15#8) pg. 6

Voltage-monitoring circuits and some typical applications. (1) Simple low-voltage. (2) Simple over-voltage. (3) Dual voltage. (4) Dual voltage with alarm. (5) Dual voltage with relay disconnect. (6) Over-voltage with discrete components. (7) Low-voltage with discrete components. (8) Over-voltage cutout. (9) Over-voltage with latching relay. (10) Over-voltage using fuse protection.
POPULAR ELECTRONICS [2] Jan 1999 (v.16#1) pg. 56

Household voltage monitor turns on an alarm if current falls below a safe level for motor-driven home appliances.
POPULAR MECHANICS Aug 1972 (v.138#2) pg. 119

Brownout alarm sounds a shrill whistle if your household electrical power dips below a safe level.
POPULAR SCIENCE Aug 1971 (v.199#2) pg. 90

Build an inexpensive expanded-scale voltmeter to monitor ac line voltage.
RADIO-ELECTRONICS Aug 1978 (v.49#8) pg. 66

Low-voltage alarm circuit is designed to work with battery powered devices. Draws little current and does not interfere with other devices powered by the battery.
RADIO-ELECTRONICS Dec 1978 (v.49#12) pg. 76

LED bar-graph display. Eight simple electronic gadgets, including a line voltage monitor.
RADIO-ELECTRONICS Oct 1979 (v.50#10) pg. 93

Simple circuit uses any common op-amp to form an analog comparator with variable hysteresis between two trip-points (one fixed and one movable).
RADIO-ELECTRONICS Jul 1981 (v.52#7) pg. 60

Low-battery indicator uses an LED to signal when the battery voltage has dropped below a pre-selected level.
RADIO-ELECTRONICS Dec 1982 (v.53#12) pg. 84

Low-battery warning. A circuit which constantly monitors the condition of batteries and signals if their voltage falls below a preset value.
RADIO-ELECTRONICS Nov 1983 (v.54#11) pg. 101

Sensing circuits. Three methods for sensing when a circuit is active. Looks at light, coil, and series dropping resistor sensing techniques.
RADIO-ELECTRONICS Mar 1984 (v.55#3) pg. 76

Power supply over/under voltage monitor is built around the Motorola MC3425/MC3525 monolithic power supply supervisory circuit.
RADIO-ELECTRONICS Aug 1984 (v.55#8) pg. 84

A handy low-voltage indicator. Low-power circuit turns on an LED, buzzer, etc. whenever the base voltage drops too low.
RADIO-ELECTRONICS Dec 1985 (v.56#12) pg. 104

Working with voltage comparators. Voltage-comparators and window-comparators are extremely versatile circuits. Here are some practical circuits that you can put to use.
RADIO-ELECTRONICS Jun 1986 (v.57#6) pg. 58
Added Info RADIO-ELECTRONICS Sep 1986 (v.57#9) pg. 17

Over-voltage indicator circuit will light an LED, sound an alarm, etc. when a particular voltage level is reached.
RADIO-ELECTRONICS Oct 1987 (v.58#10) pg. 101

An under-voltage monitor circuit sounds an alarm if voltage drops below 6.7 volts.
RADIO-ELECTRONICS Nov 1987 (v.58#11) pg. 41

Automobile battery monitor circuit has three LEDs to indicate four voltage levels (11, 12, 13, and 14 volts).
RADIO-ELECTRONICS Jan 1988 (v.59#1) pg. 22

Explanation of a "crowbar" circuit which monitors the output voltage of a regulated power supply.
RADIO-ELECTRONICS Jan 1988 (v.59#1) pg. 22
Correction RADIO-ELECTRONICS Apr 1988 (v.59#4) pg. 16

Powerline monitor shows the AC line voltage and the relative noise level on the line. Can also be used to test line filters quickly and easily. Est. cost: $45.
RADIO-ELECTRONICS Nov 1988 (v.59#11) pg. 55, 73

Glitches in the power line. A look at their causes and monitoring equipment.
RADIO-ELECTRONICS Apr 1990 (v.61#4) pg. 39
Added Info RADIO-ELECTRONICS Jun 1990 (v.61#6) pg. 12

Voltage-detection circuit will light an LED whenever a variable power supply is putting out a particular voltage (5-, 10-, 15-volts).
RADIO-ELECTRONICS May 1990 (v.61#5) pg. 8