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Multivibrator Circuits
Multivibrators:  #'s - K      L - Z
 
 

Last Updated: October 18, 2017 05:04 AM

Circuits Designed by Dave Johnson, P.E. :

1 Second One Shot Circuit - This timer circuit draws only 3ua of current, and can be powered by DC supplies ranging from 3v to 15v.  The circuit produces accurate pulses whose time can easily be adjusted, based on the R1 x C1 time constant.  The time should not change, . . . Hobby Circuit designed by David A. Johnson P.E.-September, 2010

1.5V Touch Activated Switch - A single 1.5v silver oxide button cell powers this complete touch activated switch circuit for 5 years.  It features both a normally open and a normally closed set of solid-state switch thermals.  It also has an adjustable sensitivity, which can be set for a touch capacitance change as small as 1 picofarad.. . . Circuit by David A. Johnson P.E.-January, 2002

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.. . . Circuit by David Johnson P.E.-February, 2002

2 Transistor Oscillators - This page has two unusual two-transistor oscillators.  I set the component values for a low frequency application.  Both circuits draw only about 1 micro amp of current. . . Circuit by David Johnson P.E.-December, 2002

Accurate One Shot Pulse Generator - This timer circuit draws only 3ua of current, and can be powered by DC supplies ranging from 3v to 15v.  The circuit produces accurate pulses whose time can easily be adjusted, based on the R1 x C1 time constant.  The time should not change,. . . Circuit by David A. Johnson P.E.-September, 2010

Advertising Badge #1 with Flashing LED - I have seen numerous flashing light badges at trade shows and conventions.  They are often handed out as gifts to promote some business.  The devices often use inefficient circuits, which cause the battery power source to be quickly depleted. . . Circuit by Dave Johnson P.E.-March, 2002

Advertising Badge #2 with Flashing LED - This circuit uses a CD4013 dual D Flip/Flop IC.  A single lithium battery will provide months of continuous LED flashing.  It also has a tiny push-button switch to turn on and off the light flashing. . . Circuit by David Johnson P.E.-March, 2002

Astable Ultra Low Power Multivibrator - Taking advantage of some new voltage comparators, this circuit can produce a nice square wave signal while drawing only 1.6 micro amps.  With the inclusion of a diode, the circuit can also produce short pulses instead of a square wave signal . . . Hobby Circuit designed by David A. Johnson P.E.-December, 2004

Automatic Timeout included with this On/Off Flip/flop Circuit - 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 . . . Hobby Circuit designed by David A. Johnson P.E.-May, 2012

Battery-Powered LED Flashing Advertising #2 - This circuit is similar to flashing LED advertising badge #1.    It uses a CD4013 dual D Flip/Flop IC.    The 74HCT74 IC in #81 does not always work.    As in #81, a single lithium battery will provide months of continuous LED flashing. . . . Hobby Circuit designed by David Johnson P.E.-March, 2002

Capacitance Proximity Switch-3 volts - This circuit was designed to provide a touch activated switch function without an external power supply.  It draws so little power that a single 3v battery will operate the circuit for many years . . . Hobby Circuit designed by David A. Johnson P.E.-February, 2002

Delayed Pulse Generator - This circuit generates a short 10ms pulse 15 minutes after a “start” pushbutton switch is activated. . . Circuit by David A. Johnson P.E.-October, 2005

D-Flip/Flop One Shot Circuit - Yes you can use cheap D flip/flop logic circuits as nice one-shot pulse generators.  This schematic shows how the popular CD4013 and the CD74HC74 can be used to generate pulses ranging from nanoseconds to seconds. . . Circuit by David A. Johnson P.E.-June, 2000

Flashing LED Advertising Badge #1 - I have seen numerous flashing light badges at trade shows and conventions.  They are often handed out as gifts to promote some business.  The devices often use inefficient circuits, which cause the battery power source to be quickly depleted . . . Hobby Circuit designed by Dave Johnson P.E.-March, 2002

Generate Short Delayed Pulse - This circuit generates a short 10ms pulse 15 minutes after a “start” pushbutton switch is activated . . . Hobby Circuit designed by David Johnson P.E.-October, 2005

H Bridge Motor Controller uses Low Power - This circuit uses a few logic gates & a 74AC240 to control power to a small gear motor . . . Hobby Circuit designed by David Johnson P.E.-July, 2005

Honeybee Counter - I designed a circuit similar to this one a long time ago to help a beekeeper count the number of bees going into or out of a hive.  The low power circuit uses a slotted opto-sensor to detect the passing bees.  The circuit advances an electronic counting. . . Circuit by David A. Johnson P.E.-July, 2000

Indicates when it is Time to Dust - I thought about this circuit when I heard that a lot cleaning personal in hotels were either dusting rooms more often than necessary or not enough.  I have not yet built and tested this circuit completely but in concept it should work. . . Circuit by David Johnson P.E.-June, 2000

Indicates when it is Time to Dust - I have used the circuit below for many different applications, which require ultra low power drain.  It uses a single CA4013 flip/flop.  One section forms a pulse generator.  The generator produces 100uS pulses at a rate of about 1 per secondCircuit Solution by David Johnson P.E.-May, 2006

It's Time to Dust Indicator - I thought about this circuit when I heard that a lot cleaning personal in hotels were either dusting rooms more often than necessary or not enough.  I have not yet built and tested this circuit completely but in concept it should work . . . Hobby Circuit designed by David Johnson P.E.-June, 2000


Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:

1 Second One Shot Circuit -  This timer circuit draws only 3ua of current, and can be powered by DC supplies ranging from 3v to 15v.  The circuit produces accurate pulses whose time can easily be adjusted, based on the R1 x C1 time constant.  The time should not change, . . . Hobby Circuit designed by David A. Johnson P.E.-September, 2010

1.5V Touch Activated Switch -  A single 1.5v silver oxide button cell powers this complete touch activated switch circuit for 5 years.  It features both a normally open and a normally closed set of solid-state switch thermals.  It also has an adjustable sensitivity, which can be set for a touch capacitance change as small as 1 picofarad.. . . Circuit by David A. Johnson P.E.-January, 2002

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.. . . Circuit by David Johnson P.E.-February, 2002

2 Transistor Oscillators -  This page has two unusual two-transistor oscillators.  I set the component values for a low frequency application.  Both circuits draw only about 1 micro amp of current. . . Circuit by David Johnson P.E.-December, 2002

Accurate One Shot Pulse Generator -  This timer circuit draws only 3ua of current, and can be powered by DC supplies ranging from 3v to 15v.  The circuit produces accurate pulses whose time can easily be adjusted, based on the R1 x C1 time constant.  The time should not change,. . . Circuit by David A. Johnson P.E.-September, 2010

Advertising Badge #1 with Flashing LED -  I have seen numerous flashing light badges at trade shows and conventions.  They are often handed out as gifts to promote some business.  The devices often use inefficient circuits, which cause the battery power source to be quickly depleted. . . Circuit by Dave Johnson P.E.-March, 2002

Advertising Badge #2 with Flashing LED -  This circuit uses a CD4013 dual D Flip/Flop IC.  A single lithium battery will provide months of continuous LED flashing.  It also has a tiny push-button switch to turn on and off the light flashing. . . Circuit by David Johnson P.E.-March, 2002

An SCR Flipflop  for Alternating Flashing Light Bulbs -  Schematic only __ Designed by G.L. Chemelec

Astable Flip Flops -  Several circuits here.  The familiar astable flip-flop circuit is a handy configuration for making flashers or generating squarewaves.  Here is a typical alternating LED flasher with the LEDs in the emitters instead of collectors as is normally done.  The bias resistors are directly connected __ Contact: Charles Wenzel of Wenzel Associates, Inc.

Astable Multivibrator -  The capacitor C charges via R1 and R2 and when the voltage on the capacitor reaches 2/3 of the supply, pin 6 detects this and pin 7 connects to 0v.  The capacitor discharges through R2 until its voltage is 1/3 of the supply and pin 2 detects this and turns off pin 7 to repeat the cycle__ 555-Timer

Astable Multivibrator -  Scroll to find this circuit.  This is an astable multivibrator circuits to alternately flash two LEDs.  The R & C values determins.   __ Designed by Bill Bowden

Astable Multivibrator -  As shown in the schematic diagram here, the astable multivibrator simply extends the modification that converted the bistable multivibrator to a monostable version of the circuit.  Now, both transistors are coupled to each other through capacitors.  Whichever transistor __ Designed by Dr W D Phillips

Astable Multivibrator Gets Hysteresis From Positive-Feedback Stage -  22-Oct-09 EDN-Design Ideas - Add hysteresis through positive feedback __ Circuit Design by Robert Larson, Seattle, WA

Astable Multivibrator Lights LED From a Single Cell -  08/21/08 EDN-Design Ideas - A classical multivibrator drives a step-up inductor to power an LED from a single cell __ Circuit Design by Luca Bruno, ITIS Hensemberger, Monza, Lissone, Italy

Astable Multivibrator Projects -  Astable or free-running multivibrators have been used in home-built amateur radio equipment for many years.  The basic circuit is a two stage amplifier with AC-coupled feedback from output to input.  One transistor stage is on    (conducting current)  __ Designed by Todd, VE7BPO

Astable Multivibrators -  Multivibrators: an old, well known and boring subject.  No - not at all: there are lots of different ways of looking a them and they are not at all what they may seem.   __ Designed by Richard Torrens

Astable Ultra Low Power Multivibrator -  Taking advantage of some new voltage comparators, this circuit can produce a nice square wave signal while drawing only 1.6 micro amps.  With the inclusion of a diode, the circuit can also produce short pulses instead of a square wave signal . . . Hobby Circuit designed by David A. Johnson P.E.-December, 2004

Automatic Timeout included with this On/Off Flip/flop Circuit -  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 . . . Hobby Circuit designed by David A. Johnson P.E.-May, 2012

Battery-Powered LED Flashing Advertising #2 -  This circuit is similar to flashing LED advertising badge #1.    It uses a CD4013 dual D Flip/Flop IC.    The 74HCT74 IC in #81 does not always work.    As in #81, a single lithium battery will provide months of continuous LED flashing. . . . Hobby Circuit designed by David Johnson P.E.-March, 2002

Bistable Flip flop -  Here are two examples of bistable flip flops which can be toggled between states with a single push button.  When the button is pressed, the capacitor connected to the base of the conducting transistor will charge to a slightly higher voltage.  When the button is released, the same capacitor will discharge back to the previous voltage causing the transistor to turn off.  The rising voltage at the collector of the transistor that is turning off causes the opposite transistor to turn on and the circuit remains in a stable state until the next time the button is pressed and released.   __ Designed by Ashish Parab

Capacitance Proximity Switch-3 volts -  This circuit was designed to provide a touch activated switch function without an external power supply.  It draws so little power that a single 3v battery will operate the circuit for many years . . . Hobby Circuit designed by David A. Johnson P.E.-February, 2002

Capacitance Touch Switch -  A single 1.5v silver oxide button cell powers this complete touch activated switch circuit for 5 years.  It features both a normally open and a normally closed set of solid state switch thermals.  It also has an adjustable sensitivity, which can be set . . . Hobby Circuit designed by David Johnson P.E.-January, 2002

CMOS Toggle Flip Flop using Laser Pointer -  The circuit below uses a CMOS dual D flip flop  (CD4013) to toggle a relay or other load with a momentary push button.  Several push buttons can be wired in parallel to control the relay from multiple locations.  A high level from the push button is coupled to the set line through a small  (0.1uF) capacitor.  The high level from the Q output __ Designed by Bill Bowden

CMOS Toggle Flip Flop using Push Button -  The circuit below uses a CMOS dual D flip flop  (CD4013) to toggle a relay or other load with a momentary push button.  Several push buttons can be wired in parallel to control the relay from multiple locations.  A high level from the push button is coupled to the set line through a small  (0.1uF) capacitor.  The high level from the Q output __ Designed by Bill Bowden

Darkroom Camera Shutter Timer -  This circuit was designed to control a film exposure shutter for a darkroom.  It has 8 time steps ranging from 0.35 seconds to 4 seconds.  It is activated by a foot switch and draws power from an external 12-volt DC supply. . . Circuit by David A. Johnson P.E.-June, 2000

Delayed Pulse Generator -  This circuit generates a short 10ms pulse 15 minutes after a “start” pushbutton switch is activated. . . Circuit by David A. Johnson P.E.-October, 2005

D-Flip/Flop One Shot Circuit -  Yes you can use cheap D flip/flop logic circuits as nice one-shot pulse generators.  This schematic shows how the popular CD4013 and the CD74HC74 can be used to generate pulses ranging from nanoseconds to seconds. . . Circuit by David A. Johnson P.E.-June, 2000

Flashing LED Advertising Badge #1 -  I have seen numerous flashing light badges at trade shows and conventions.  They are often handed out as gifts to promote some business.  The devices often use inefficient circuits, which cause the battery power source to be quickly depleted . . . Hobby Circuit designed by Dave Johnson P.E.-March, 2002

Gated Oscillator Emulates a Flip-Flop -  03/16/95 EDN-Design Ideas - The gated oscillator in Fig 1 holds its existing state when disabled rather than being forced high or low-a singular property.  Further, you can generate an output at one-half the input frequency if you choose R1 and C so that the oscillator changes state just once when its input goes high.  This configuration eliminates a flip-flop.    __ Circuit Design by Einar Abell, ADA Instruments, Three Rivers, CA

Generate Short Delayed Pulse -  This circuit generates a short 10ms pulse 15 minutes after a “start” pushbutton switch is activated . . . Hobby Circuit designed by David Johnson P.E.-October, 2005

Generator has independent pulse width, frequency -  11/11/99 - EDN-Design Ideas - A common circuit in electronics is the square-wave, astable multivibrator  (one-shot) , which is useful for various purposes, such as timing circuits and audible alarms.  The most common way to generate the desired square wave is to use the inexpensive 555 timer.  The need sometimes arises for a square wave with fixed frequency but variable pulse width or vice versa.    __ Circuit Design by Davinder Oberoi

H Bridge Motor Controller uses Low Power -  This circuit uses a few logic gates & a 74AC240 to control power to a small gear motor . . . Hobby Circuit designed by David Johnson P.E.-July, 2005

Honeybee Counter -  I designed a circuit similar to this one a long time ago to help a beekeeper count the number of bees going into or out of a hive.  The low power circuit uses a slotted opto-sensor to detect the passing bees.  The circuit advances an electronic counting. . . Circuit by David A. Johnson P.E.-July, 2000

Indicates when it is Time to Dust -  I have used the circuit below for many different applications, which require ultra low power drain.  It uses a single CA4013 flip/flop.  One section forms a pulse generator.  The generator produces 100uS pulses at a rate of about 1 per secondCircuit Solution by David Johnson P.E.-May, 2006

Indicates when it is Time to Dust -  I thought about this circuit when I heard that a lot cleaning personal in hotels were either dusting rooms more often than necessary or not enough.  I have not yet built and tested this circuit completely but in concept it should work. . . Circuit by David Johnson P.E.-June, 2000

It's Time to Dust Indicator -  I thought about this circuit when I heard that a lot cleaning personal in hotels were either dusting rooms more often than necessary or not enough.  I have not yet built and tested this circuit completely but in concept it should work . . . Hobby Circuit designed by David Johnson P.E.-June, 2000


Multivibrators:  #'s - K      L - Z

 


Imagineering Ezine    Discover Solar Energy Dave Johnson & Associates Faraday Touch Switches



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