by Ron Demcko AVX Corporation Fellow, USA presented by R.Demcko at the 2nd PCNS 10-13th September 2019, Bucharest, Romania as Keynote 1 and rated by PCNS attendees as the best Keynote presentation Abstract In the past, system power budgets and data/operating speeds were wide and slow respectively. This allowed passive component selection and consideration to occur at the end of the design cycle. Today in...
R 5.1 NTC THERMISTORS In this section we shall describe some non-linear resistor styles, meaning that they don’t follow Ohm’s law. Simplified, the resistor material consists of doped granule compounds containing various oxides that by means of binders have been pressed to a desired shape and then sintered. The terminals either are inserted into the resistor body or soldered to metallized surfaces. There are...
The need for small, adjustable resistors created trim potentiometers. They lack the potentiometer shaft and are operated through an adjustment screw or a rotor. The setting needs to be maintained during handling and environmental influence. Thus, the contact pressure of the wiper is high. The setting stability is specified as a voltage change expressed in percent of input voltage. The first trimming potentiometers had...
According to IEC precision potentiometers are classified as Type 1. They exist in both bushing mount styles and in servo applications. In the latter case high demands are made for rotational life and low torque. Such potentiometers are supplied with ball bearings. If they in addition are sealed against moisture this will influence the torque. The solution of such problems implies explicit requirement specifications...
R 4.2.1 Power potentiometers Power potentiometers are as a rule wirewound. They are wound on a ceramic body and lack, due to heat dissipation concerns, encapsulation in casings or housings. Often they have a touch protection of silicone lacquer, cement or enamel and they are readily used as rheostats. If we turn the shaft of a rheostat towards zero resistance it is not unusual...
