Simple fixture determines leakage of capacitors and semiconductor switches

Simple fixture determines leakage of capacitors and semiconductor switches

1484
Views
0 Comments

The circuit in Figure 1a comprises a voltage follower, IC1 , and the reference-voltage source of IC2. IC1 is an Analog Devices AD8661 op amp, which has a guaranteed input-bias current of no more than 1 pA and a typical input-bias current of 0.3 pA (Reference 1), and IC2 is an Analog Devices ADR391 precision voltage reference (Reference 2). The manufacturer trims the input offset voltage of this op amp not to exceed 100 µV, and the typical value is 30 µV. These properties suit this amplifier for observing self-discharging of almost any type of capacitor. The leakage currents of solid-tantalum capacitors and those having high-quality plastic dielectrics are well above the input-bias current of voltage follower IC1. The CUT (capacitor under test) initially charges to the reference-voltage level of 2.5V by connecting Point A to the output of IC2. Subsequently, at some convenient time, Point A disconnects from the source of the reference voltage. A DVM (digital voltmeter) measures the output voltage of the follower at some reasonable time.

Simple fixture determines leakage of capacitors and semiconductor switches – [Link]

Mike is the founder and editor of Electronics-Lab.com, an electronics engineering community/news and project sharing platform. He studied Electronics and Physics and enjoys everything that has moving electrons and fun. His interests lying on solar cells, microcontrollers and switchmode power supplies. Feel free to reach him for feedback, random tips or just to say hello :-)

view all posts by admin
Subscribe
Notify of
guest
0 Comments
Inline Feedbacks
View all comments
Archives