In this video I explain the building blocks of a 555 chip and how it interacts with the components you connect around it to become a “Timer”!
I talk through each stage of the 555 including
- Voltage Divider (comprising of three 5K resistors)
- Two Comparators
- The Flip-Flop
- NPN and PNP Transistors utilised for Discharge and Reset
We explore the Charge and Discharge times as the capacitor oscillates between the 1/3rd and 2/3rd voltage levels and verify that with an oscilloscope.
If you are interested in the handy configurable Resistor boards I utilised you can purchase them from Amazon here:-
amzn.to/3RYiX75
For more information about Voltage Dividers, see one of my previous videos here:-
• What Are Voltage Divid...
Timeline
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00:00:00 - Introduction
00:00:59 - PKAE Electronics Intro Theme
00:01:09 - Internal Stages starting with Voltage Divider
00:02:29 - Two Comparators
00:04:16 - Control Voltage Pin
00:04:32 - Flip-Flop & Output Driver Stage
00:05:40 - SR Flip-Flop Explained
00:07:27 - NPN Discharge Transistor
00:07:50 - PNP Transistor for External Reset
00:08:14 - Summary of Stages
00:08:39 - Comparator/Flip-Flip Experimenting (Theory)
00:15:54 - Comparator/Flip-Flip Experimenting (Bench Testing)
00:17:58 - Astable Circuitry - External Capacitor and Two Resistors
00:21:20 - Bench Testing Astable Mode
00:22:48 - Datasheet Astable Circuit Diagram
00:23:27 - Control Voltage Capacitor (Stability)
00:23:53 - Timing Calculations (On and Off Times)
00:25:41 - Bench Testing Timings with Oscilloscope
00:29:06 - Timing Summing Up
00:29:17 - Frequency Calculation
00:30:12 - Wrap Up.
26 июл 2024