Digital Experiments

Home	www.play-hookey.com	Thu, 10-17-2019
\| Direct Current \| Alternating Current \| Semiconductors \| Digital \| Logic Families \| Digital Experiments \| Computers \| \| Analog \| Analog Experiments \| Oscillators \| Optics \| HTML Test \|
\| Getting Started \| Preparations \| DL Experiments \| RTL Experiments \| DTL Experiments \| TTL Experiments \| Multivibrators \| Basic Clock Sources \| Counter and Display \|

Digital Experiments

One of the best ways to learn electronics of any kind is to have some actual components on hand and build the circuit you want to explore. Then you can test it, make adjustments, and test again as you figure out just what is going on in the circuit.

Modern student labs often use simulators such as SPICE, or programming systems such as Matlab to test the circuit in a theoretical way. This does have the advantage that real components aren't required, and can't be damaged or destroyed by excessive voltages or currents. However, it also has the disadvantage that all circuit behavior is calculated from theoretical models, so the student never sees the typical variations that may occur when using real components in a real physical environment.

If you're going to work with electronics at all, you will eventually have to work with real parts in real circuits. Therefore, these pages will all be designed, tested, and written as real-world physical experiments.

Getting Started

Before you can start experimenting, you must gather together the required parts and equipment.

Preparations

Once you have all the pieces, you still need a power supply and a minimum means of input and output.

DL Experiments

Diode Logic (DL) is very simple, but also very limited. Here we find out just what DL can do, as well as what it cannot do, and why.

RTL Experiments

When transistors became inexpensive enough to use them in large numbers, they were applied to logic circuits.

DTL Experiments

As faster logic circuits were demanded, diode logic was combined with transistors.

TTL Experiments

The technology of integrated circuitry made it possible and practical to build variations on DTL that improved both the input and output circuitry of logic gates. We can't do it all with discrete components, but we can examine how the input circut evolved.

Multivibrators

"Multivibrator" is a fancy name for a digital circuit that can take on more than one state without any input changes. Here are the basic variations on this theme.

Basic Clock Sources

Most sequential circuits require accurate and stable timing to control their behavior. In other cases, we may want manual inputs (such as a person pressing a button to request a "walk" signal to enable them to safely cross a busy street).

Counter and Display

Building up to a human-readable numeric display.