What can we really do just with resistors and sources Anything of Interest There are lots of resisto

1
What can we really do just with resistors and
sources ?Anything of Interest?There are lots
of resistor type elements you can put in a
circuit.
2
Photoresistors

• Photoresistors detect changes in ambient light
  levels. The resistance varies with the intensity
  of light on the device.

3
Photoresistors

• In the dark, the resistance is very high, in the
  1 megohm range.
• When illuminated, the resistance may drop to a
  few hundred ohms.
• These are also often called Light-dependent
  Resistors (LDRs).

4
Light Sensor - Photoresistor
Light dependent resistor. Cadmium Sulfide type.
Changes resistance with light.
5
Force Sensing Resistors

• As their name implies, force sensing resistors
  use the electrical property of resistance to
  measure the force (or pressure) applied to a
  sensor. A force sensing resistor is made up of
  two parts.
• The first is a resistive material applied to a
  film.
• The second is a set of digitating contacts
  applied to another film.
• The resistive material serves to make an
  electrical path between the two sets of
  conductors on the other film. When a force is
  applied to this sensor, a better connection is
  made between the contacts, hence the conductivity
  is increased.

6
Force Sensing Resistors
7
Resistance versus Force
8
Bend Sensors

• The bend sensor uses a resistive ink that changes
  resistance when it is stretched/compressed.
• The blobs of resistance ink become closer when
  you bend the material.

9
(No Transcript)
10
(No Transcript)
11
Thermistors

• Thermistors are analog temperature sensors. they
  are resistors that change value with temperature.
  They are available for a variety of temperature
  ranges in both F and C.
•