Tech Briefs Magazine - October 2023 - Sensor-11

harvested to generate power, up to
about 1.6mW/cm2.
Photovoltaic
Photovoltaics take any light source,
such as the sun, LED, or indirect sunlight,
and produce electricity. This
method produces about 3.2mW/cm2
per 100 Lux. For reference, grocery
stores and retail lighting are often
around 1000 Lux, making these locations
ideal for indoor light energy
harvesting.
The power (voltage × current)
available to the load varies with
changing light levels as illustrated in
this family of curves (Figure 2).
Solar modules, for the most part,
are very linear in their output,
current tracks with light intensity.
However, that changes when you
drop below 10 percent of the full
sunlight
Sunlight
+ +
+
intensity of 1000W/m2.
Once it drops below that, the series
resistance of the solar panel
starts to take over and the open
circuit voltage starts to drop. As
can be seen, for lower light levels,
the maximum available voltage at
no load (Voc) is reduced. That reduces
the amount of output power
available.
The maximum power point, the
maximum voltage x current product,
on these curves is at the knee of the
curve. The knee of the curve gets flatter
in varying light conditions, from
200 to 1000 Lux. For the illustrated
panel, it varies from 2.4V at 200 Lux
up to 3V at 1000 Lux.
Why Charge Controllers?
The power available from the
photovoltaic (PV) system is a function
of both the output of the PV
source and the charge state of the
storage battery. The function of a
charge controller is to maximize
the power delivered to the load
by adjusting the balance between
these two.
Two common types of charge controllers
are maximum power point
tracking (MPPT) and pulse width modulation
(PWM).
True MPPT does just that, it tracks
the maximum power of the solar panel
in real time. This technology holds
the solar panel at its maximum power
point and provides the maximum
Sensor Technology, October 2023
Figure 1. (Image: PowerFilm)
200 Lux
2.6
2.4
2.2
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
Figure 2. (Image: PowerFilm)
power from the panel in changing
lighting conditions.
A PWM charger connects and disconnects
the panel to and from the battery
in short bursts and monitors the voltage
of the battery to determine the state of
charge. It will only work with solar panwww.techbriefs.com
els
that have a higher voltage than the
battery they are charging. The greatest
disadvantage of the PWM circuit is the
loss of power between what's available
from the solar panel and what actually
goes into the battery. On average, you
get about 30-35 percent less power
11
1
2
Voltage (V)
3
4
PowerFilm Indoor Light Series
400 Lux
600 Lux
800 Lux
1000 Lux
Anti-reflection coating
Front electrode (-)
N-type (N+)
+
P-type (N-)
Back electrode (+)
Current
+
- -
+
+ +
- - -
+
-
Current (mA)

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Tech Briefs Magazine - October 2023

Table of Contents for the Digital Edition of Tech Briefs Magazine - October 2023

Tech Briefs Magazine - October 2023 - Intro
Tech Briefs Magazine - October 2023 - Sponsor
Tech Briefs Magazine - October 2023 - Cov1
Tech Briefs Magazine - October 2023 - Cov2
Tech Briefs Magazine - October 2023 - 1
Tech Briefs Magazine - October 2023 - 2
Tech Briefs Magazine - October 2023 - 3
Tech Briefs Magazine - October 2023 - 4
Tech Briefs Magazine - October 2023 - 5
Tech Briefs Magazine - October 2023 - 6
Tech Briefs Magazine - October 2023 - 7
Tech Briefs Magazine - October 2023 - 8
Tech Briefs Magazine - October 2023 - 9
Tech Briefs Magazine - October 2023 - 10
Tech Briefs Magazine - October 2023 - 11
Tech Briefs Magazine - October 2023 - 12
Tech Briefs Magazine - October 2023 - 13
Tech Briefs Magazine - October 2023 - 14
Tech Briefs Magazine - October 2023 - 15
Tech Briefs Magazine - October 2023 - 16
Tech Briefs Magazine - October 2023 - 17
Tech Briefs Magazine - October 2023 - 18
Tech Briefs Magazine - October 2023 - 19
Tech Briefs Magazine - October 2023 - 20
Tech Briefs Magazine - October 2023 - 21
Tech Briefs Magazine - October 2023 - 22
Tech Briefs Magazine - October 2023 - 23
Tech Briefs Magazine - October 2023 - 24
Tech Briefs Magazine - October 2023 - 25
Tech Briefs Magazine - October 2023 - 26
Tech Briefs Magazine - October 2023 - Comsol-1A
Tech Briefs Magazine - October 2023 - Comsol-2A
Tech Briefs Magazine - October 2023 - Comsol-3A
Tech Briefs Magazine - October 2023 - Comsol-4A
Tech Briefs Magazine - October 2023 - Comsol-5A
Tech Briefs Magazine - October 2023 - Comsol-6A
Tech Briefs Magazine - October 2023 - Comsol-7A
Tech Briefs Magazine - October 2023 - Comsol-8A
Tech Briefs Magazine - October 2023 - Comsol-9A
Tech Briefs Magazine - October 2023 - Comsol-10A
Tech Briefs Magazine - October 2023 - Comsol-11A
Tech Briefs Magazine - October 2023 - Comsol-12A
Tech Briefs Magazine - October 2023 - Comsol-13A
Tech Briefs Magazine - October 2023 - Comsol-14A
Tech Briefs Magazine - October 2023 - Comsol-15A
Tech Briefs Magazine - October 2023 - Comsol-16A
Tech Briefs Magazine - October 2023 - Comsol-17A
Tech Briefs Magazine - October 2023 - Comsol-18A
Tech Briefs Magazine - October 2023 - Comsol-19A
Tech Briefs Magazine - October 2023 - Comsol-20A
Tech Briefs Magazine - October 2023 - Comsol-21A
Tech Briefs Magazine - October 2023 - Comsol-22A
Tech Briefs Magazine - October 2023 - Comsol-23A
Tech Briefs Magazine - October 2023 - Comsol-24A
Tech Briefs Magazine - October 2023 - Comsol-25A
Tech Briefs Magazine - October 2023 - Comsol-26A
Tech Briefs Magazine - October 2023 - Comsol-27A
Tech Briefs Magazine - October 2023 - Comsol-28A
Tech Briefs Magazine - October 2023 - Comsol-29A
Tech Briefs Magazine - October 2023 - Comsol-30A
Tech Briefs Magazine - October 2023 - Comsol-31A
Tech Briefs Magazine - October 2023 - Comsol-32A
Tech Briefs Magazine - October 2023 - Comsol-33A
Tech Briefs Magazine - October 2023 - Comsol-34A
Tech Briefs Magazine - October 2023 - Comsol-35A
Tech Briefs Magazine - October 2023 - Comsol-36A
Tech Briefs Magazine - October 2023 - 27
Tech Briefs Magazine - October 2023 - 28
Tech Briefs Magazine - October 2023 - 29
Tech Briefs Magazine - October 2023 - 30
Tech Briefs Magazine - October 2023 - 31
Tech Briefs Magazine - October 2023 - 32
Tech Briefs Magazine - October 2023 - 33
Tech Briefs Magazine - October 2023 - 34
Tech Briefs Magazine - October 2023 - 35
Tech Briefs Magazine - October 2023 - 36
Tech Briefs Magazine - October 2023 - 37
Tech Briefs Magazine - October 2023 - 38
Tech Briefs Magazine - October 2023 - 39
Tech Briefs Magazine - October 2023 - 40
Tech Briefs Magazine - October 2023 - 41
Tech Briefs Magazine - October 2023 - 42
Tech Briefs Magazine - October 2023 - 43
Tech Briefs Magazine - October 2023 - 44
Tech Briefs Magazine - October 2023 - 45
Tech Briefs Magazine - October 2023 - 46
Tech Briefs Magazine - October 2023 - 47
Tech Briefs Magazine - October 2023 - 48
Tech Briefs Magazine - October 2023 - 49
Tech Briefs Magazine - October 2023 - 50
Tech Briefs Magazine - October 2023 - 51
Tech Briefs Magazine - October 2023 - 52
Tech Briefs Magazine - October 2023 - Cov3
Tech Briefs Magazine - October 2023 - Cov4
Tech Briefs Magazine - October 2023 - MD-Cov1
Tech Briefs Magazine - October 2023 - MD-Cov2
Tech Briefs Magazine - October 2023 - MD-1
Tech Briefs Magazine - October 2023 - MD-2
Tech Briefs Magazine - October 2023 - MD-3
Tech Briefs Magazine - October 2023 - MD-4
Tech Briefs Magazine - October 2023 - MD-5
Tech Briefs Magazine - October 2023 - MD-6
Tech Briefs Magazine - October 2023 - MD-7
Tech Briefs Magazine - October 2023 - MD-8
Tech Briefs Magazine - October 2023 - MD-8A
Tech Briefs Magazine - October 2023 - MD-8B
Tech Briefs Magazine - October 2023 - MD-8C
Tech Briefs Magazine - October 2023 - MD-8D
Tech Briefs Magazine - October 2023 - MD-9
Tech Briefs Magazine - October 2023 - MD-10
Tech Briefs Magazine - October 2023 - MD-11
Tech Briefs Magazine - October 2023 - MD-12
Tech Briefs Magazine - October 2023 - MD-13
Tech Briefs Magazine - October 2023 - MD-14
Tech Briefs Magazine - October 2023 - MD-15
Tech Briefs Magazine - October 2023 - MD-16
Tech Briefs Magazine - October 2023 - MD-17
Tech Briefs Magazine - October 2023 - MD-18
Tech Briefs Magazine - October 2023 - MD-19
Tech Briefs Magazine - October 2023 - MD-20
Tech Briefs Magazine - October 2023 - MD-21
Tech Briefs Magazine - October 2023 - MD-22
Tech Briefs Magazine - October 2023 - MD-23
Tech Briefs Magazine - October 2023 - MD-24
Tech Briefs Magazine - October 2023 - MD-25
Tech Briefs Magazine - October 2023 - MD-Cov4
Tech Briefs Magazine - October 2023 - Sensor-Cov1
Tech Briefs Magazine - October 2023 - Sensor-Cov2
Tech Briefs Magazine - October 2023 - Sensor-1
Tech Briefs Magazine - October 2023 - Sensor-2
Tech Briefs Magazine - October 2023 - Sensor-3
Tech Briefs Magazine - October 2023 - Sensor-4
Tech Briefs Magazine - October 2023 - Sensor-5
Tech Briefs Magazine - October 2023 - Sensor-6
Tech Briefs Magazine - October 2023 - Sensor-7
Tech Briefs Magazine - October 2023 - Sensor-8
Tech Briefs Magazine - October 2023 - Sensor-9
Tech Briefs Magazine - October 2023 - Sensor-10
Tech Briefs Magazine - October 2023 - Sensor-11
Tech Briefs Magazine - October 2023 - Sensor-12
Tech Briefs Magazine - October 2023 - Sensor-13
Tech Briefs Magazine - October 2023 - Sensor-14
Tech Briefs Magazine - October 2023 - Sensor-15
Tech Briefs Magazine - October 2023 - Sensor-16
Tech Briefs Magazine - October 2023 - Sensor-17
Tech Briefs Magazine - October 2023 - Sensor-18
Tech Briefs Magazine - October 2023 - Sensor-19
Tech Briefs Magazine - October 2023 - Sensor-20
Tech Briefs Magazine - October 2023 - Sensor-21
Tech Briefs Magazine - October 2023 - Sensor-22
Tech Briefs Magazine - October 2023 - Sensor-23
Tech Briefs Magazine - October 2023 - Sensor-24
Tech Briefs Magazine - October 2023 - Sensor-25
Tech Briefs Magazine - October 2023 - Sensor-26
Tech Briefs Magazine - October 2023 - Sensor-27
Tech Briefs Magazine - October 2023 - Sensor-28
Tech Briefs Magazine - October 2023 - Sensor-29
Tech Briefs Magazine - October 2023 - Sensor-30
Tech Briefs Magazine - October 2023 - Sensor-31
Tech Briefs Magazine - October 2023 - Sensor-32
Tech Briefs Magazine - October 2023 - Sensor-Cov3
Tech Briefs Magazine - October 2023 - Sensor-Cov4
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