1. Electronic Product Design Do it Yourself
Finally…
LAUNCH!!
Dr. Y S Rao

2. Digitization of Objects Analog vs. Digital

3. Beware of the computer! computers + SoCs = hardware / software mix
complete change in device interaction
ever-growing number of critical applications

4. On/OFF Control

5. ON/OFF Switch (current)

6. Transistor can act as a Switch

8. EX: Light Failure Warning System using Transistor as a Switch

9. Introducing Delay in ON/OFF
RC constants
A simple resistor and capacitor can be used to control the amount of time that it takes for an output signal to reach a specific voltage. This is particularly useful when you reset a device, to ensure, for example, that a pin does not reach logic high (0.7*VCC for CMOS) or pass logic low (0.3*VCC for CMOS) before x microseconds, giving the rest of the system time to perform some other tasks before-hand.
This simple calculator will tell you how many milliseconds are required to reach the specific output voltage (Vc), based on the supply voltage (V), the resistor value (R) and the capacitor value (C). The resistor value is assumed to be in K ohms, the capacitor in microfarads, and the calculated delay will be in milliseconds.
The formula used to calculate the delay is: t = -log((V-Vc)/V)R*C
To calculate Vc at a specific time, the formula can be modified to: Vc = V-(V*exp(-t/(R*C)))

10. Example
The following image shows the results of a 2.0K resistor and a 0.1uF capacitor using a 3.3V supply.
The blue line is the HW reset, and the yellow line is the output of the RC pair. You can see that it takes about 230us (.23ms) to reach 2.3V, which is roughly logic high on a CMOS device using 3.3V logic (0.7VCC).
Issue of Tolerance

11. Transistor with Delay

12. MOSFET Switch

13. Digital ICs Sinking & Sourcing

14. Noise Margin Ability to tolerate noise without changes in output voltage

15. A Typical Microcontroller
RAM
Flash
EEPROM
I/O
Core
Clock
Reset
Timers
Power
Comm
Analog

16. Technology Comparison

17. Integration

18. IC Packages