Designing and building a 9v battery replacement using supercapacitors
Introduction
Part 1 of this video tutorial introduces the viewer to the reasons why the author of this tutorial wants to design and build such a battery replacement.
Several types of classic 9v batteries are described, showing how many hours of life they would provide to an average digital multimeter and comparing their efficiency from a price point of view.
The reasons why a 9v battery is used in a digital multimeter are presented and supercapacitors are introduced as a potential replacement for such bulky, inefficient (when it comes to providing energy to digital multimeters) batteries.
Supercapacitors are not ideal replacements though - several advantages and disadvantages are presented, along with possible "fixes" or "improvements" that alleviate some of the disadvantages.
- 00:10 Introduction
- 03:10 9v battery types, discharge rates
- 18:30 Why are 9v batteries used in digital multimeters?
- 23:00 Why supercapacitors?
- 26:30 Benefits & trade-offs
Part 2 shows viewers how to select a boost switching regulator that would be most suitable for creating such battery replacement, one that would be able to take out as much energy from the surpercapacitors, generating the higher voltage digital multimeters expect, with a reasonably good efficiency.
Several factors that influence the selection of a boost regulator are explained: availability, package type, price, extra components required to complete the circuit being just a few of them.
Once a boost switching regulator is selected, the datasheet is browsed and the application circuit presented in the datasheet is altered to be more suitable for the footprint of a 9v battery.
The modified circuit is then re-created in the free circuit simulator software LTSpice IV, the basic simulation showing the efficiency and the limitations of the boost regulator in regard to minimum voltage required to obtain the desired output voltage and current.
- 00:10 Selecting a DC-DC boost switching regulator
- 06:00 Things to look for when deciding on a DC-DC boost switching regulator
- 14:00 LT1037 datasheet and application circuit
- 24:00 Adapting datasheet application circuit for the 9v battery footprint
- 28:00 Simulating the circuit using LTSpice IV
In Part 3, the circuit is actually built. After a brief presentation of the components needed for the circuit, changes to the planned are explained.
As the circuit is finalized, mistakes are detected and corrected and everything is ready to be tested using a home-made constant current load Incomplete
