0
The 555 timer can be configured in a variety of ways. When used in a tachometer circuit it is configured as a monostable vibrator, ie a device that has one stable state on its output terminal. Let's consider that state as "OFF" .
If a trigger pulse is sent to the input it will turn "ON" for a fixed period of time set by the circuit time constant then turn "OFF" again.
Consider a single cylinder four stroke petrol engine firing once every two revolutions and revolving at 1000 rpm. A strong pulse will be generated from its ignition circuit 500 times a minute - or every 120 milliseconds. With some
pulse shaping and amplitude limiting, a pulse can be derived from this to trigger the monostable vibrator from "OFF" to "ON"
Let's assume that the monostable time constant components are chosen to make the fixed width output pulse be 20 Milli seconds and a current measuring meter is connected to the output and adjusted to read one fifth of full scale deflection - ideally marked "1000" on its scale.
Now as the speed of the engine is increased, there will be more and more 20 Milli second pulses at the output and the meter reading will rise linearly in proportion to the engine speed because the meter movement will respond to the average current.
In this particular case, with a 20 millisecond output pulse, when 5000 rpm is reached the trigger pulses are now arriving every 24 Milli seconds and the 555 output will be "ON" for 83% of the time. The meter will have reached full scale deflection.
Above 5000 rpm this example would soon become unstable and inaccurate.
Pulses from other types of rotating machinery can be derived optically or magnetically to trigger a tachometer like this.
Add your answer:
Earn +20 pts
How do pie charts work?
work like diagrams
What are the steps in calculating the quartile of group data?
Re-arrange the data in increasing order.If there are n data points, calculate (n+1)/4.Find the data point in position (n+1)/4, using interpolation if required. This is the LOWER QUARTILE.Find the data point in position 3*(n+1)/4, using interpolation if required. This is the UPPER QUARTILE.In n is large (>30, say), don't bother to add 1: just work with the observations in the n/4th and 3n/4th positions.
Where should the fulcrum of a lever to make work harder?
closer to the point of where the work is being pushed/done
What is percentage of work in to work out?
I dont know but 20 x 20 is 400
What is the main reason for using a data table to collect data?
Data tables help you keep information organized. If you're collecting data from work, school, an experiment, or scientific research, saving it in a data table will make it easier to look up later. Data tables can also help you make graphs and other charts based on your information.
How do weigher work?
A small section of the conveyor belt is weighed using Load Cells and the belt speed is measured using a tachometer. The outputs from the Load Cells and Tachometer are fed into an electronic integrater box which calculates and displays the rate, which is usually in tons per hour.
How do belt weighers work?
A small section of the conveyor belt is weighed using Load Cells and the belt speed is measured using a tachometer. The outputs from the Load Cells and Tachometer are fed into an electronic integrater box which calculates and displays the rate, which is usually in tons per hour.
How does a digital stopwatch work ?
A digital stopwatch operates using an electronic clock circuit that counts elapsed time in increments of milliseconds, seconds, minutes, and hours. When you press the start button, the timer begins counting time, and when you press stop, it halts the count. The display then shows the recorded time.
Mazda b2500 tach works speedometer does not?
The Mazda tachometer and the speedometer have separate cables. The tachometer cable probably does not work properly. Change the tachometer cable.
If you had a speedometer with a tachometer and you replaced it with a speedometer without a tachometer will it work?
it sure would work.. behind the dashboard are plugs for each function. one for tachometer, one for speedometer, fuel, water temp. ect.. if your new dash doesn't have a tachometer it will not interfere with the speedomet aspect of it. but you will not have a tach obviously. that sucks kid
Your tachometer on your 1996 ford explorer does not work why?
One possibility is that the tachometer connections to the circuit board of the cluster have become corroded. It is also possible that the tachometer has just become worn out and needs to be replaced.
How does a clockwork egg timer work?
A clockwork egg timer works by using a spring mechanism that slowly unwinds over a set amount of time. When the timer is set, the spring tightens, causing the timer to count down until the spring fully unwinds and a bell or chime alerts that the time is up.
Why does your tachometer not work on my 2005 Kia Sedona?
rev counter not working
Why will the tachometer odometer and speedometer not work on a 1995 Silverado?
because they are broken.
What would make a 92 sc400 miss fire and tachometer not work properly?
There are several things that can cause your engine to misfire and the tachometer to not work properly. The most common cause is a malfunctioning vacuum hose.
Is a computer an analog device?
The majority of modern computing devices are digital. That means they work by using many on and off type electrical signals. Analog computers work by using vary ranges of constantly-changing signals in real-time without converting them to digital sequences first.
My tachometer only works about once per year. How do you check for loose connections on the tachometer in a 99 Honda Civic Si?
If the tachometer only works a few times a year the VSS is malfunctioning. This can occur when oil is spilled on the unit and messes with the sensor. Cleaning the sensor will allow the tachometer to work properly.
