Traffic Light Control Circuit

Posted on Feb 5, 2014

This page features a circuit that has twenty open collector outputs that turn on one at a time in a continuous, unidirectional loop sequence. The circuit uses the 74LSxx family of TTL integrated logic devices. The circuits are designed to drive light emitting diodes or low current, low voltage incandescent lights but can also drive other loads of

Click here to download the full size of the above Circuit.

up to 80 milliamps. As logic circuits go, the 20 Step circuit is fairly simple but due to the nature of the TTL Logic devices used, care must be taken when wiring these circuits. Simply put; The neater the wiring the better. NOTE:The 20 Step Circuit does not work in circuit simulation programs. The likely cause is that this circuit uses input states that force the outputs of the 74LS145 drivers to be turned off. These states would normally not be used with these devices and are probably not programmed into the simulator`s software. If you would like to make use of these circuits, take the time to find and read at least the first 2 pages of the manufactures datasheets for the integrated circuits. Using Google, search for "74ls(part number)" in the first box and "PDF" in the second box on the advanced search page. The circuit does not drive the 74LS145`s directly but uses a 74LS107 JK Flip-Flop and four 74LS32 dual input OR gates to control to the inputs to the two 74LS145 output drivers. The 74LS107 and 74LS32 are used to create disallowed states in the output drivers alternately. The disallowed states prevent any of the ten outputs on that particular device from being turned ON while the other 74LS145 is in counting to ten. This produces a system where only one of the 74LS145`s is able to produce a LOW output state at a time. In essence the circuit counts to 10 twice in succession rather than counting to 20 in a single...

Visit page

Leave Comment

characters left:

Related Circuits

Silent Radio LED sign to Arduino

Working on the brightness problem, I know that the 4017 design did not work well because there was no way to turn off the sign while updating the shift registers. As a result I went back to having...

Laser Microphone

This was a final project for an optics class EE 134 at Stanford. It was an open-ended project to make a fully functioning laser microphone the class was geared to demonstrate optics and photonics...

relay circuits

Remove the 6 mm screw holding on the lower rear fairing cover. This is the black plastic piece the spark plug protectors are attached to. Do not remove the lower rear fairing covers, only the...

Single Capacitor Powers Audio Mixer

Micropower and low-voltage op amps allow you to build high-performance analog-signal processors that require no batteries or wall transformers. Instead, you can use a capacitor as a power source....

Berkeley Bolometer Group - Research

Bolometer systems would be simplified considerably if all components could be made photolithographically on a single substrate. We are developing a design for a single-substrate array with several...

Design of VLSI Systems

Clock signals are the heartbeats of digital systems. Hence, the stability of clock signals is highly important. Ideally, clock signals should have minimum rise and fall times, specified duty...

ARCHITECTURES FOR VIDEO PROCESSING

The first question we would like to answer is: what do we mean nowadays for video processing In the past, more or less till the end of the 80`s there where two distinct worlds: an analog TV world...

DC Lessons In Electric Circuits

A meter is any device built to accurately detect and display an electrical quantity in a form readable by a human being. Usually this "readable form" is visual: motion of a pointer on a scale, a...

New Circuits

Zero consumption Anti-theft High power Code Switch for E-Bike Batteries

This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
Ultrasonic distance finder circuit

The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Simple Metal detector circuit with CD4030

Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Fully automatic watering circuit for flower pots

Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
Simple deep searching metal detector circuit

The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
Sub-Harmonic Bass Converter for Electric Guitars

The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
Echo Depth Sounding Sonar for Boats

In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
100W HiFi Audio Amplifier Circuit

This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
Plant-Pot Water Level Indicator Circuit

A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....

Create NOW your QR MENU for your Restaurant / Hotel / Bar / Caffe,

Comprehensive ordering/paying features. fully personalized to suit your Business.

Update Anytime! Easy and Simple!

Popular Circuits

Loudspeaker Box Amplifier schematic

This original design is a variation on a well-known design, examples of which can be found in a...

Proximity-switch

A 3-x -3-inch piece of circuit board, or similar size metal object which functions as the...

Two-simple-temperature-to-time-converters

Both of these converters use CMOS inverters. Figure 105-1A shows a free-running circuit having...

Capacitor Esr Measurer

The equivalent series resistance (ESR) of a capacitor can be measured using this circuit and an...

QRP HF LINEAR AMPLIFIER Circuit

This project was a particular surprise for me in that the BC547 (equiv 2N2222) can be used to...

12VDC to 220VAC Inverter with Sine Wave Output

Here the 50W inverter circuit build based power MOSFET FQB45N03 and IC TL494. This inverter will...

Selfrunning Free Energy 5 KW Kapanadze 3

If the principle of work of the Kapanadze device is the same principle as discovered by Tesla...

AB4YD Amateur Radio Page

This project was inspired by a series of QST articles by Hayward, W1PH. I based my rig on his...