Integrated circuit course

Comparison of logic families Since RTL was introduced in the early 1960s. there has been a steady progression in technology; the design engineer now has a wide choice of integrated circuit ranges and operating parameters. It is apparent that speed/power comparisons are not sufficient in themselves. Other important parameters to be considered are noise immunity, supply voltage requirements and fan out. Power supply requirements Each logic type has different power supply requirements and since system economics can be greatly affected by the cost of power supplies it is important to establish exact power supply parameters. With the exception of the 74C series of devices, all series in the 74 family are of transistor-transistor-logic (TTL) construction. The 74C series (which is of CMOS construction) is pin compatible with all 74 family members and therefore the generic TTL title usually includes it. TTL 74 family and CMOS 4000 family devices have generally superseded all

Thyristors Some confusion exists over the use of the term thyristor. Here it is taken as a generic title, the silicon controlled rectifier (s.c.r.) being one particular type. An s.c.r. with its equivalent circuit and symbol is shown below. With G open-circuit 01 is cut off, so the device will not conduct unless VAK is made sufficiently positive for it to avalanche. If the gate is made positive /CJ flows. Now /CJ is base current for 0 2 and fez is base current for 01 • Therefore /CJ brings on 0 2 and the cumulative action makes both transistors saturate, i.e. the voltage across the device falls to a minimum and it is in the condition of a closed switch. Once the s.c.r. is on, the gate voltage is not required to sustain it. In fact the gate cannot be used to turn it off, and this must be done by reducing VAK to a very small voltage. To switch a thyristor on without any gate voltage the device must be made to avalanche. Such a device, which will avalanche in either direction in a cont

CMOS data e l e c t i o n b y d e v i c e n u m b t r Device Description 4000           Dual 3-input NOR gate plus Inverter 4001           Quad 2-input NOR Gate  

Standard wire gauge and standard drill sizes BSI standard metric sizes of copper Metric wire sizes: turns per 10 mm  

Metric sizes of insulated round winding wires

Trigonometric relationships Transistor circuits and characteristics Wavelength-frequency conversion table Metres to Kilohertz Transistor testing Although the following table cannot be used to accurately find the characteristics of an unknown transistor, if it is stepped through it will indicate whether the transistor is good or bad. Use of a meter with a 100 times resistance scale is assumed, which does not have a high current output. Radio interference The Radio Investigation Service of the Department of Trade and lndu.stry now devotes its efforts against those operating radio transmitters without a licence ('pirates') and those who abuse the terms and conditions of the licence. Far less time is spent investigating complaints of interference by owners of domestic radio and electronic equipment, which is prone to pick up interference because of unsuitable internal circuit screening, poor quality design, inadequate maintenance, improper tuning and, with

Statistical formulae The arithmetic mean of a set of numbers Xx, X2,…, XN is their average. It is the sum of the numbers divided by the number of numbers and is denoted bv X Particles of modern physics Stable particles are listed below. Calculus Differentiation Mensuration