You may be losing patiencea little and asking yourselves, just where this article is leading. I can offer a partial answer. It should impart something reasonably meaningful about the installation in a car. To do this, the above shown component is absolutely necessary. You may already have come across something like this in connection with the strange display behaviour of the fuel- and temperature gauges.

You're dead right, it is a voltage regulator, because with battery tension alone, a digital electronic circuit can do nothing. What we need, at least in this case, are 5 volts, the so-called TTL-voltage. Thus, the 12V-plus lead is connected to the left pin (input) and the minus lead to the center pin (COMMON), which is responsible for the vehicle as well as for the circuit. On the right pin then, is the OUTPUT of 5 V+.

Now wait!, before you take any further steps, we still have to discuss the currents to be managed. This component can handle a maximum of 1 Ampere on the output, there are also smaller ones. And, it must be cooled! Thermal transfer compound must be applied to the metal back-plate and then mounted onto a sufficiently sized heat- sink. So, if you didn't already know it, you have some idea of what a Z-diode is, because that (with a few additional components), is exactly what this is all about. 08/11