A Plethora Of NE-555 data - NE555 Tutorials Page

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Copyright © January 28th 1996 - Updated August 16th 2011 .......... Brought to you by Unitech Electronics Pty. Ltd. Please note, if you wish to print out this page, it will require 14 sheets of standard A4 paper ( Portrait mode ). Please, be aware of this.

Mouse-pointer over the chip to stop the NE-555 moving

NE-555 TIME CONSTANTS - Simple graphical representations


    The capacitor charging slows down as it nears its expected charge however, in actual  fact it never 
    reaches the full +Vcc supply voltage.  Please note: This is the nature of the beast, remember this.
    That being the case, the maximum charge it receives in the timing circuit (66.6% of the supply voltage) 
    which is a little over the charge received after a time constant ( 63.2% ). ( Q = I x t )


    The capacitor discharges slowly down until it almost discharges fully, however they never quite reach 
    the ground potential, this is also the nature of the beast.  This means there will always be a minimum 
    voltage present in a circuit that can be measured in as it operates at greater than zero. In some cases, 
    it is desirable to place a high value resistor across the supply rails to help "bleed-out" the capacitors.   
    The Timing circuit is approximately 63.2% of the +Vcc supply voltage.

Mouse-over to stop the NE-555 Chip moving.


    The discharge time (t) of a capacitor to discharge expotentially to a theoretical zero also takes time 
    and this can be shortened by decreasing resistance (R) to the flow of current. (t= R x C )

    Without a doubt, waiting for the capacitor to charge while holding a stopwatch has to be up there
    with watching grass grow, especially if the capacitor "C" is 1,000uF and the "R" is 1Meg or larger.
 
    This can literally take over 1 hour for the whole thing to change state, while observing on the CRO.
    So, We built a special digital timer, counting upwards and incrementing and only displaying in seconds 
    and triggering off the NE-555's "change in state" to do this mundane task. Observing this without the 
    digital seconds counter would have been about as exciting as watching paint dry,.... seriously.

Basic NE-555 Operating Modes:

The NE-555 timer has two basic operational modes: one shot (monostable) and the other as astable. In the one-shot mode, the NE-555 acts like a monostable multivibrator. A monostable is said to have a single stable state and that is the "off" state. Whenever it is triggered by an input pulse, the monostable switches to its temporary state. It remains in that state for a period of time determined by an R-C network. It then returns to its stable state, awaiting a possible trigger.

So, in other words, the monostable circuit generates a single pulse of a fixed time duration each time it receives and input trigger pulse. Thus the name one-shot. One-shot multivibrators are used for turning some circuit or external component on or off for a specific length of time. It is also used to generate delays. When multiple "one-shots" are cascaded, a variety of sequential timing pulses can be generated. Those pulses will allow you to time and sequence a number of related operations.

The other basic operational mode of the NE-555 is as and astable multivibrator. An astable multivibrator is simply and oscillator. The astable multivibrator generates a continuous stream of rectangular off-on pulses that switch between two voltage levels. The frequency of the pulses and their duty cycle are dependent upon the R-C network values.

Basic NE-555 One-Shot ( Monostable ) Operation:

Fig. 4 shows the basic circuit of the NE-555 connected as a monostable multivibrator. The use of the word "multivibrator" here implies it oscillates, well, it does but once only. It should be referred to as a "toggle-ator" as it toggles from one state and stops in another state, ie: going from high to low or low to high, depending on the circuit it is being used in. An external RC network is connected between the supply voltage and ground. The junction of the resistor and capacitor is connected to the threshold input which is the input to the upper comparator.

The internal discharge transistor is also connected to the junction of the resistor and the capacitor. An input trigger pulse is applied to the trigger input, which is the input to the lower comparator.

With that circuit configuration, the control flip-flop is initially reset. Therefore, the output voltage is near zero volts. The signal from the control flip-flop causes T1 to conduct and act as a short circuit across the external capacitor. For that reason, the capacitor cannot charge. During that time, the input to the upper comparator is near zero volts causing the comparator output to keep the control flip-flop reset.


    Notice how the monostable continues to output its pulse to pin 3 regardless of
    the inputs "swing" back up. The reason for this is because the output is only 
    triggered by the input pulse, the output actually depends on the capacitor charge CX.

Basic NE-555 Monostable Mode:


    The NE-555 in fig. 9 A is shown here in it's utmost basic mode of operation as 
    a triggered monostable.    One immediate observation is the extreme simplicity 
    of this circuit. Only two components to make up a timer, a capacitor and a resistor. 
    And for noise immunity maybe a capacitor on pin 5. 
    Due to the internal latching mechanism of the NE-555, the timer will always 
    time-out once triggered, regardless of any subsequent noise (such as bounce) 
    on the input trigger (pin 2). 
    This is a great asset in interfacing the NE-555 with noisy sources. 
    Just in case you don't know what 'bounce' is: bounce is a type of fast, 
    short term noise caused by a switch, relay, etc. and then picked up by the input pin.

The trigger input is initially high (about 1/3 of +V). When a negative-going trigger pulse is applied to the trigger input (see fig. 9a), the threshold on the lower comparator is exceeded. The lower comparator, therefore, sets the flip-flop. That causes T1 to cut off, acting as an open circuit. The setting of the flip-flop also causes a positive-going output level which is the beginning of the output timing pulse.

The capacitor now begins to charge through the external resistor. As soon as the charge on the capacitor equal 2/3 of the supply voltage, the upper comparator triggers and resets the control flip-flop. That terminates the output pulse which switches back to zero. At this time, T1 again conducts thereby discharging the capacitor. If a negative-going pulse is applied to the reset input while the output pulse is high, it will be terminated immediately as that pulse will reset the flip-flop.

Whenever a trigger pulse is applied to the input, the NE-555 will generate its single-duration output pulse. Depending upon the values of external resistance and capacitance used, the output timing pulse may be adjusted from approximately one millisecond to as high as on hundred seconds. For time intervals less than approximately 1-millisecond, it is recommended that standard logic one-shots designed for narrow pulses be used instead of a NE-555 timer. IC timers are normally used where long output pulses are required. In this application, the duration of the output pulse in seconds is approximately equal to:

T = 1.1 x R x C (in seconds)


    The output pulse width is defined by the above formula and with relatively few 
    restrictions, timing components R(t) and C(t) can have a wide range of values. 
    There is actually no theoretical upper limit on T (output pulse width), only practical ones.

    The lower limit is 10uS. You may consider the range of T to be 10uS to infinity, 
    bounded only by R and C limits. 
    Special R(t) and C(t) techniques allow for timing periods of days, weeks, and 
    even months if so desired.

    However, a reasonable lower limit for R(t) is in the order of about 10Kilo ohm, 
    mainly from the standpoint of power economy. 
    (Although R(t) can be lower that 10K without harm, there is no need for this 
    from the standpoint of achieving a short pulse width.) A practical minimum for 
    C(t) is about 95pF; below this the stray effects of capacitance become 
    noticeable, limiting accuracy and predictability. Since it is obvious that the 
    product of these two minimums yields a T that is less the 10uS, there is much 
    flexibility in the selection of R(t) and C(t). Usually C(t) is selected first to 
    minimize size (and expense); then R(t) is chosen.

    The upper limit for R(t) is in the order of about 15 Mega ohm but should be 
    less than this if all the accuracy of which the NE-555 is capable is to be achieved.


    The absolute upper limit of R(t) is determined by the threshold current plus the 
    discharge leakage when the operating voltage is +5 volt. 
    For example, with a threshold plus leakage current of 120nA, this gives a 
    maximum value of 14M for R(t) (A very optimistic value). 
    Also, if the C(t) leakage current is such that the sum of the threshold current 
    and the leakage current is in excess of 120 nA the circuit will never time-out 
    because the upper threshold voltage will not be reached. 

    Therefore, it is good practice to select a value for R(t) so that, with a voltage drop 
    of 1/3 V+ across it, the value should be 100 times more, if  practical.

    So, it should be obvious that the real limit to be placed on C(t) is its leakage, 
    not it's capacitance value, since larger-value capacitors have higher leakages 
    as a fact of life.   Low-leakage types, like tantalum or NPO, are available and 
    preferred for long timing periods. 

    Sometimes input trigger source conditions can exist that will necessitate some 
    type of signal conditioning to ensure compatibility with the triggering requirements 
    of the NE-555. 
    This can be achieved by adding another capacitor, one or two resistors and a 
    small signal diode to the input to form a pulse differentiator to shorten the input 
    trigger pulse to a width less than 10uS (in general, less than T). 
    Their values and criterion are not critical; the main one is that the width of the 
    resulting differentiated pulse (after C) should be less than the desired 
    output pulse for the period of time it is below the 1/3 V+ trigger level.

There are several different types of NE-555 timers manufactured today. The LM-555 from National was the most common one in the days of late 1996.. The Exar XR-L555 timer is a micropower version of the standard NE-555 offering a direct, pin-for-pin compatible substitute device with an advantage of a lower power operation making it ideal for battery and other portable applications etc.

It is capable of operation of a wider range of positive supply voltage from as low as an incredible 2.7 volt minimum up to 18 volts maximum, Previously 15V !. At a supply voltage of +5V, the L555 will typically dissipate of about 900 microwatts, making it ideally suitable for many diverse and innovative battery operated circuits. The internal schematic of the L555 is very much similar to the standard NE-555 but with additional features like 'current spiking' filtering, lower output drive capability, higher nodal impedances, and better noise reduction system. A true and positive step forwards.

See at Maxim's ICM-7555, and also at Sanyo's website LC-7555 models are a low-power, general purpose CMOS design version of the standard NE-555, also with a direct pin-for-pin compatibility with the regular NE-555. It's main advantages are very low timing / bias currents, low power-dissipation operation and an even wider voltage supply range of as low as 2.0 volts to 18 volts.

At 5 volts the 7555 will dissipate about 400 microwatts, making it also highly suitable for battery operation. The internal schematic of the 7555 (not shown) is however totally different from the normal NE-555 version because of the different design process with cmos technology. It has much higher input impedances than the standard bipolar transistors used. The cmos version removes essentially any timing component restraints related to timer bias currents, allowing resistances as high as practical to be used. This very versatile version should be considered where a wide range of timing is desired, as well as low power operation and low current sync'ing appears to be important in the particular design.


   A couple years after Intersil, Texas Instruments came 
   on the market with another cmos variation called the LINCMOS (LINear CMOS) or Turbo 555. 

    In general, different manufacturers for the cmos 555's reduced the current from 
   10mA to 100µA while the supply voltage minimum was reduced to about 2 volts, 
   making it highly ideal type for 3 Volt applications. 
   The CMOS version is the choice for battery powered circuits, however, on the 
   negative notes side for the CMOS 555's is the reduced output current, both for 
   sync and source, This is not really a problem as a FET or a NPN or PNP transistor 
   can be added as an amplifier or a heavier switching output device if so required. 

   For a simple comparison, the regular NE-555 can easily deliver a 200mA output 
   versus between 5mA  to  50mA for the 7555. 

   On the work test bench the regular NE-555 reached a limited output frequency 
   of 180Khz while the 7555 easily surpassed the 1.1Mhz mark and the TLC555 
   ceased at about 2.4Mhz.  Components used were 1% metal film Resistors and 
   quality low-leakage capacitors, supply voltage used was 10volt DC regulated


    Some of the less desirable properties of the regular NE-555 are high supply 
    current, high trigger current, double output transitions, and inability to run with 
    very low supply voltages. 
    These problems have been remedied in a collection of CMOS successors.


    A word of caution about the regular NE-555 timer chips; the NE-555, along with some 
    other timer ic's, generates a huge (approx 150mA) supply current glitch during each 
    output transition.  Be very sure to use a hefty bypass capacitor over the power connections 
    near the timer chip. And even so, the NE-555 may have a tendency to generate double 
    output transitions.

Basic NE - 555 ASTABLE ( MULTIVIBRATOR ) Operation:

Basic NE-555 Astable (multivibrator) operation:

Figure 9B shows the NE-555 connected as an astable multivibrator. Both the trigger
and threshold inputs ( pins 2 and 6 ) to the two comparators are connected together and to
the external capacitor. The capacitor charges toward the supply voltage through the two
resistors, R1 and R2. The discharge pin ( 7 ) connected to the internal transistor is
connected to the junction of those two resistors.
When power is first applied to the circuit, the capacitor will be uncharged, therefore, both
the trigger and threshold inputs will be near zero volts (see Fig. 10A). The lower comparator
sets the control flip-flop causing the output to switch high. That also turns off transistor T1.
That allows the capacitor to begin charging through R1 and R2. As soon as the charge on the
capacitor reaches 2/3 of the supply voltage, the upper comparator will trigger causing the
NE-555's internal "flip-flop" to reset.

That causes the output to switch low. Transistor T 1 also conducts. The effect of T 1 conducting
causes resistor R2 to be connected across the external capacitor. Resistor R2 is effectively
connected to ground through internal transistor T1. The result of that is that the capacitor
now begins to discharge through R2.

NE - 556 NE - 558 ICM - 7555 Timer chips

The only major differences between the single NE - 555, the NE - 556 (a dual 555) and a NE - 558 (a quad 555)
are the power rails. Both NE-556 and NE-558 are 14-pin chips) with different pin configurations for power and Ground.

For the other remaining pins it will require you to download from here the PDF for each device from our web site
for further study before using as errors are costly and fried chips (semi's) do not smell too good.

The 8-pin NE-555 Versus the ICM-7555 Note: The CMOS version ICM-7555 by NXP requires studying before using.

It has its own characteristics for power in, power out and over-all power consumption. The ICM-7555 in Astable
or multivibrator mode will oscillate up to 500MHz as opposed to the earlier 1971-1979 NE-555's of a mere 200MHz.

It is pin-for-pin compatible, however being a CMOS device, the internal ICM-7555's circuitry differs in many ways.
Most measurements are shown as being in Pico-Amps as opposed to the NE-555 being in Milli-Amps . Therefore,
we strongly urge you to please download the PDF and examine the distinct advantages of either device before using.

Data Sheet downloads are available here on our web site

At the point where the voltage across the capacitor reaches 1/3 of the supply voltage,
the lower comparator is triggered.

This event causes the control "flip-flop" to set and the resultant output to go high logic.
Transistor T 1 (Fig.3) cuts off and again the result is, the capacitor begins to charge.

This charging and discharging cycle continues to repeat with the capacitor alternately being recharged
and discharged, as the internal two comparators cause the flip-flop to be repeatedly set and reset,
depending on the frequency set by you, the designer of the circuit layout.
The net result is an output that is a continuous stream of nice clean rectangular usable "clock" pulses.

The frequency of operation of the astable circuit is dependent upon the values
of R1, R2, and C. The frequency can be calculated with the following formula:

f = 1/(.693 x C x (R1 + 2 x R2))

The Frequency f is in Hz, R1 and R2 are in ohms, and C is in farads. Typically Micro-Farads (uF) are used.
The time duration between these pulses is known as the 'period' and is usually designated with as 't'.
The pulse is on for t1 seconds, then off for t2 seconds.
The total period (t) is t1 + t2 (see fig. 10).
That time interval is related to the frequency by the familiar relationship:

f = 1/t or t = 1/f

The time intervals for the on and off portions of the output depend upon the values
of R1 and R2. The ratio of the time duration when the output pulse is high to
the total period is known as the duty-cycle. The duty-cycle can be calculated
with the formula:

D = t1/t = (R1 + R2) / (R1 + 2R2)

You can calculate t1 and t2 times with the formulas below:

t1 = .693(R1+R2)C

t2 = .693 x R2 x C

The NE-555, when connected as shown in Fig. 9b, can produce duty-cycles in the range of
approximately 55 to 95%. A duty-cycle of 80% means that the output pulse is on
or high for 80% of the total period. The duty-cycle can be adjusted by varying the values
of R1 and R2.

Basic NE-555 Applications:

There are literally thousands, maybe 10's of thousands of individually unique ways
that the ubiquitous NE-555 can be used in any or all electronic circuits.
In almost every case, however, the basic circuit is either a one-shot or an astable.
The application usually requires a specific pulse time duration, operation frequency,
and duty-cycle.
Additional components may have to be connected to the NE-555 to interface the device
to external circuits or devices. In the remainder of this experiment, you will build both
the one-shot and astable circuits and learn about some of the different kinds of
applications that can be implemented.

Basic simple NE - 555 Free sample Circuits:

We have added-in a range of NE-555 circuit samples below for your perusal. Please experiment with them
and have fun, electronics should be fun for everyone. Try ( within reason ) different component values and
use the simple formulas mentioned earlier to calculate your final results. Make only small changes and observe
the results and note your results, do everything in increments. Do not exceed 200KHz oscillation on any NE-555 !

The most important thing to remember:
Note: For correct by-the-book monostable operation with the NE-555 timer, remember the "negative-going" trigger
pulse width should be kept quite short when compared to the required output pulse "width".

Values for the external timing resistor and capacitor can either be determined from the previous formulas.
However, you should stay within the ranges of resistances shown earlier to avoid the use of large value
electrolytic capacitors, since they can tend to be leaky. Tantalum capacitors, low E.S.R. low leakage
electrolytics or mylar types and some brands of monolithic ceramics should always be used.

For +Vcc supply noise "immunity" on most timer circuits we recommend a the simple addition of a ceramic
0.01uF (10nF) capacitor between pin 5 and ground. In all circuit diagrams below we have used the LM-555CN
timer IC from National Semiconductor, but the NE-555 and other brands should not give you any problems.

Now, please bare in mind, the noise on the supply line that is created by a NE-555 operating. It is always good
electronic practice to place fairly large value capacitors, say to the order of 470uF 16V or 1000uF 16 V
when using the NE-555 as we and many other NE-555 users have noted the spurious "dirty" harmonics from most brands
of NE-555 chips. The addition of a 10uF tantalum capacitor, a 470uF electrolytic and a ceramic 0.01uF seems to work.

FREE NE - 555 CIRCUITS to EXPERIMENT WITH"

Darkness Detector: Figure 1 (above)

This is indeed an interesting circuit which has the facility to sound an alarm if it
suddenly gets too dark compared to the previous light level.
A simple use for this circuit would be its use to notify someone when a globe
(or light bulb) fails to operate or is open circuit.

The darkness detector uses a regular cadmium-sulphide LDR (Light Dependent Resistor)
to sense the "quick" absence of light falling on the LDR and to operate a small and quite
cheap 8 ohm speaker. The LDR enables the alarm when light falls below a certain level.
Calibration could be effective if a 47K potentiometer was added in series with the LDR.

Power Failure Alarm: Figure 2 (above)

This circuit can be used as a simple yet effective audible 'Power-Failure Alarm'.
In this cunning application it uses the NE-555 timer as an oscillator biased off
by the presence of line-based DC voltage at Pin 7.

When the line voltage fails (monitored 9V line), the bias is removed, and the alarm tone
will be heard in the piezo-electric speaker. Choose a Piezo around the 105dB mark.

R1 and C1 provide the DC bias that charges capacitor C1 to over 2/3 Vcc voltage, in
this case, about 6.0 V thereby holding the timer output low. Diode D1( 1N4148 / IN914 )
provides DC bias (approx 5.4V) to the timer-supply pin 8 and optionally float-charges a
rechargeable nickel metal hydride 9 volt battery across D2. R4 10 ohms is optional if needed.
When the line power fails, the 9V input via D3, DC is applied to the timer through D2.
resulting in a very audible sound. Experimentation with higher voltages such as 12 V DC
can result in some novel and some interesting educational concepts coming to fruition.

Fig. 3 Tilt Switch: Figure 3 (above)

This clever ICM-7555 application is basically an alarm circuit, it displays how to use a ICM-7555 timer and a simple small
glass mercury switch to indicate an alarm condition, either by forced movement or by the act of tilting a protected item.

The ICM-7555 is there to serve as a "pseudo-latch", by closing the circuit, the 470K is pulled "low", pin 2 is sent low
and triggers the ICM-7555 retaining or " memorising " the last closed circuit state by the closing of the mercury switch.
Resetting is via SW-2. Output " high " from pin 3 drives the base of Q1. Check first your transistor "specs" for base
saturation values and calculations. A 2N2222 should switch well with R3 as 1K ~ 1K8 depending of course on the load,
a relay with a 350 ~ 600 ohms coil will suffice. Don't forget to add a protection diode across the relay pointing to +ve.

As far as we know, there is no other metal which is a liquid at room temperature. Mercury (Hg) is such a metal and has some
unusual and unique properties which are diametrically opposed to the properties of water surface tension and side adhesion.

The mercury switch is carefully inserted into a short 20mm tube of plastic then mounted in its normally 'open' position, in which
this allows the ICM-7555 timer's " trigger " pin 2 to stay high being fed via R1 470K. The ICM-7555 has lower current usage.

Pin 3 output will stay low, as established by C1 0.1uF on startup acting upon pin 4. When the mercury switch is disturbed
via vibration or movement thus causing its contacts to be bridged momentarily by the liquid mercury, the ICM-7555 latch is set to a
high output level where it will stay even if the switch is returned to its starting position thus driving the base of Q1 via Rx (R3)
which may be as low as 560 Ohms. Please observe static electricity CMOS handling procedures with this CMOS device.

The high output can be used to enable an alarm of the visual or the audible type. Reset switch SW2 will silence the alarm and
reset the latch. Note: Due to the required characteristics of the Vcc +ve turn on, C1 must be ceramic 0.1uF ( 100 nF ) capacitor.

Photo-Electric Eye Alarm: Figue 4 (above)

The Photo-Electric Eye Alarm is similar circuit like the Darkness Detector of Figure 1.
The same type of Photo-LDR (light dependent resistor) is employed as in Figure 1.
The pitch tone for the speaker can be set and adjusted with the 470K ohm potentiometer.
One of the great ideas here, is to send a beam of light via a tube approximately 30 cm long
with a standard 5 watt bulb (or similar) across a doorway or even a room and use this
beam of light as an alarm, so, when the beam is broken, the NE-555 provides an audible
indication of a "intrusion". This is similar to LED based systems currently in use today.

The Pocket Metronome: Figure 5 (above)

A Metronome is a one of the most widely used devices in the entertainment and music industry.

With a rhythmic 'toc-toc' sound you can set the tempo of a piece of music to the correct beats per minute,
the speed of which can be adjusted with the VR1 250K potentiometer, providing the desired "beat" or "tempo".
R1 and R2 with C1 form the approximate 50% duty cycle.

A metronome is also a very handy tool if you new to learning to play a music instrument and need to maintain
the correct rhythm as it was intended by the original lyric and rhythm composers on the sheet music or "by ear".

It can be made to fit neatly in a small "Jiffy Box" and as it is powered by a 9 Volt battery, the size can be reduced
to what ever compact size you need. Remember to drill the holes before attempting to mount and adhere your small 8 ohm
speaker with contact adhesive.

Using a sharp scriber, make a circular scribe around the outside of the speaker and then divide the circle into 4 equal
parts then into 8 and using smaller "rings" say... 12mm from the centre, make smaller scribe circles intersecting the 8 lines.

Now, make a larger circle of , say 24mm from the centre and at each of the 8 lines drill your holes. You should now have 17 holes
including the one in the centre.

Drill a series of 4mm ~ 5mm holes in a circular pattern to facilitate the "toc-toc" sound existing the small plastic jiffy-box.
A volume control could be added, but only if required.We suggest a 100 ohm ~ 250 ohm potentiometer after the 10uF C2 capacitor

C-W Practice Oscillator: Figue 6 (above)

C-W is the abbreviation for Continuous Wave or simply Morse-Code. S.O.S. or dot-dot dash-dash dot-dot .. -- ..

You can utilise this neat circuit to practice the morse-code with this circuit, perhaps to get your amateur (ham) radio license .

Surprisingly enough, morse is the "fall-back" form of communications, that is to say, once all radio communication has gone down
morse signals can still be made using the most primitive of "spark transmitters", even a car coils can be used in the hands of a
person versed in morse code. Dots are a quick noise, dashes are three to four times the width of a dot in morse code.

It is very often used to communicate between submarines (visually by blinking the light from the periscopes) and is still taugh in
all military schools as a back-up communication, just in case modern radios "bite the dust". Very useful communications indeed.

The VR1 150K potentiometer is for the 'pitch' and the 15K is to adjust the speaker's volume.

The "Key" SW2 is a standard morse code key, these are available in most good electronics shops.

C-W Monitor: Figure 7 (above)

This ingenious little NE-555 circuit monitors the morse code " on-air " via the "tuned circuit" connected
to pin 4 and the short wire 900mm antenna.

The 100K potentiometer controls the tone and pitch.

It is open to a small amount of experimentation for the end user to achieve the best results.

We found it quite fascinating how simple and easy to use it was based on the circuit details.

Click this picture for more circuits

12 Minute (760 seconds) Timer: Figure 8 (above)

This neat little circuit can be used as a quiet time-out warning for Ham Radio operators as required by The Australian
Communications Commission (A.C.C.) requires that a Amateur Radio (HAM) operator identify his or her station by giving his
or her call-sign at least every 10 minutes, basically operating under the same rules that govern commercial AM and FM
radio stations. This can present itself as a small challenge, especially when carrying on lengthy intense discussions
as well as in depth conversations resulting in one actually loosing all track of time while "chatting" with another.
A visual indication is used with no "beep", however if you wish, you can add-on a small NE-555 oscillator circuit.

The NE-555 comes to the rescue in this simple quiet circuit and is used as a one-shot so that a visual warning indicator
becomes active after 10-minutes. You set it for whatever time you wish the NE-555 to take to trigger and change state.
Maybe 10 mins or less, you choose, with the circuit suggested here, you can set the time from 6 seconds to 760 seconds.

It can be further cascaded to a second NE-555 that is setup as a simple "beep" oscillator as in FIGURE 6A .
At the commencement of conversation, turn it on, the red LED will light-up, next remember to the reset switch
which will causes the Green LED to light up. After timing out the green LED extinguishes and the RED LED turns on.

The circuit (Fig.8) shows R2 as 2K2, this circuit can operate still well without the R2 connected. Upon experimentation,
it was found that virtually any value, for instance up to 250K ohms worked without effect and the timing or the operation,
noting that connecting the CRO probe will trigger the NE-555. It was also revealed that by hanging a small 30cm (1ft)
insulated wire off pins 2 & 4 "in situ" and connected to pin 2, the mere "close" contact with that insulated
wire triggered the NE-555 to change states. Be aware of the created "sensitivity" to induced "noise" by having the NE-555
configured in this manner. Here in the described circuit we used a 2K2 resistor as that was what was "laying around" at the time.

Operation is simple:
After 10 minutes, set by the 4M7 (4.7M) potentiometer VR1, the 'Red' LED will light to warn the operator that he or she must
identify and , if the circuit in FIGURE 6A is implemented, a short "beep" from an aditional NE-555 oscillator circuit will assist in
sticking to the A.C.C. rules. Using a trusty digital stop watch , adjust VR1 to indicate 10 minutes or as close to it as you can.
Sitting there, waiting for the prescribed 10 minutes or even less to occur is about as boring as watching a small block of ice melt.
We can be well assured that the A.C.M.A. sits there, highly productively, wasting time just to catch you. Your taxpayer dollars at work?

The A.C.M.A rules the waves .... Oh really? .... the air-waves that is aka " the radio/TV spectrum ".
Yes Folks, the Australian Government actually believes it owns the Radio and TV spectrum

We had absolutely no idea that they actually " own " the air-waves or spectrum. This begs the question, who did they buy them from ?
We are of the firm belief that the air-waves or radio spectrum exists in nature and as such, no one entity can claim ownership of it.

It states on the A.C.M.A. website from time to time that they are auctioning-off parts of the radio spectrum. Now our simple understanding
of common law is, in order to sell/auction something, you must first and foremost, 100% own the said item that you are selling/auctioning.

That is to state, you hold clear and free legal tile of the said goods. It must not be encumbered or under a caveat of repossession etc.
We guess we must have missed reading the part that states that the Government is exempt and above the so-called law and therefore
over-rules everyone. Quite Interesting ! In two hundred and thirty years, the ownership of Australia has transformed dramatically.

This reeks of a certain similarity to the insane scams of people claiming they own the moon and selling off "moon real-estate",
or other concepts which are just as absurd, trying to sell sunshine as a merchantable commodity, yes, maybe they will tax it? but
that of course is a folly in itself, but none-the-less, the Australian Government claims ownership of our radio spectrum, how quaint!

That also begs a further question, just how far do they assert ownership of the spectrum ? Does it stop at the edge of space or what ?
To date, no-one can direct us in the direction of how, when and why the Government became the said owners of a naturally occurring
intangible item such as a radio spectrum. The spectrum cannot be bottled, boxed or controlled by anyone, it existed long before
Captain James Cook ( a runt of a man) and his bunch of invading pirates/tourists arrived on Australia's shores, bringing with him,
so-called British justice, a fair go for everyone, recognition and respect of the traditional owners land rights, yeah right !... As if !!

It is a pity that Cook and his crew did not learn to get along with the Australian Aboriginal population, there was so much wealth
of knowledge that could have been exchanged, however being sent here to conquer and establish a colony for British and some Irish
"so-called" prisoners was high on Cook's "to do list" and any native titles were quickly squashed by the stoke of a pen and a musket
bullet, so ... the bullying started right then, so " might is right " and do not try to change it and sadly it continues very much today.

In the Sandwich Islands or Hawaii as we know it today, the local people sorted this " little runt " out, Captain James Cook died by
being speared to death. Obviously the inhabitants of the Sandwich Islands knew how to deal with these sort of invading people.

So, does the Government have some monopoly over all the area of Australia extending from terrestrial earth to a distance out in space ?

Curious questions ? Under section 52 of the Trade Practices Act, selling/offering for sale when you do not have 100% ownership is fraud.
Upon reading these "so-called" laws, there are several that apply in simple recognition of the truth, you cannot sell something, nor auction
something nor for that matter attempt to trade, hire, sell, auction anything that you do not legally own. It is against the rules. Full stop.

This monopoly was set up almost two centuries ago with absolutely no consultation with the traditional owners of the lands that Cook and
his invading red coats and as well as those who followed him, all set up an illegal regime in the name of one King George 3rd (a nutter).

Having asked the question: Who did they buy it from and when and how much was paid, these questions were all rejected and we were
directed to a Government A.C.M.A. website and given directions to read a certain PDF. This said PDF did in no manner state or contain
these words eg: " ownership ", " payment " or the limits and sizes of the claimed ownership of this radio spectrum. Is this fraudulent ??

For more information about the Government's A.C.M.A. web site click on C-tick info gadget (below)

Click below to go to page 1 Click below to go to page 3

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