Generate pwm using ic 555: Add a diode - Revision history

Mol: /* Method 2; Longer low time: Add a Diode */

2024-08-05T16:28:09Z

Method 2; Longer low time: Add a Diode

← Older revision		Revision as of 19:28, 5 August 2024
Line 31:		Line 31:
	The simulation file: [[File:555 diode 300 300.circuitjs.txt]]		The simulation file: [[File:555 diode 300 300.circuitjs.txt]]

	The '''leakage current''' through ''R_2'' can be eliminated by introducing a second diode ''D_2'' in series with that. This will make the output identical if R<sub>1</sub> and R<sub>2</sub> are identical. See the image above. The corresponding simulation file is [[File:555 diodes2 300 300.circuitjs.txt]]. Adding one more resistance (or potentiometer) to make it more symmetric. This is discussed in more detailed in the next chapter, because the two potentiometers can be easily replaced by a one.		The '''leakage current''' through ''R_2'' can be eliminated by introducing a second diode ''D_2'' in series with that. This will make the output identical if R<sub>1</sub> and R<sub>2</sub> are identical. See the image above. The corresponding simulation file is [[File:555 diodes2 300 300.circuitjs.txt]]. Adding one more resistance (or potentiometer) to make it more symmetric. This is discussed in more detailed in the next chapter, because the two potentiometers can be easily replaced by a one. The file is [[File:555 diodes2 300 300 300.circuitjs.txt]].

Mol: /* Method 2; Longer low time: Add a Diode */

2024-08-05T16:24:40Z

Method 2; Longer low time: Add a Diode

← Older revision		Revision as of 19:24, 5 August 2024
Line 6:		Line 6:
	555 diode RanalysisContour.png\| The contour and surface plot of varying resistances.		555 diode RanalysisContour.png\| The contour and surface plot of varying resistances.
	Ic555 diode2 R.pdf\|Added the second diode. This will make the output identical if R<sub>1</sub> and R<sub>2</sub> are identical.		Ic555 diode2 R.pdf\|Added the second diode. This will make the output identical if R<sub>1</sub> and R<sub>2</sub> are identical.
			Ic555 diode2 R3.pdf\|One more resistance (or potentiometer) to make it more symmetric. This is discussed in more detailed in the next chapter, because the two potentiometers can be easily replaced by a one.
	</gallery>		</gallery>

Line 30:		Line 31:
	The simulation file: [[File:555 diode 300 300.circuitjs.txt]]		The simulation file: [[File:555 diode 300 300.circuitjs.txt]]

	The '''leakage current''' through ''R_2'' can be eliminated by introducing a second diode ''D_2'' in series with that. This will make the output identical if R<sub>1</sub> and R<sub>2</sub> are identical. See the image above. The corresponding simulation file is [[File:555 diodes2 300 300.circuitjs.txt]].		The '''leakage current''' through ''R_2'' can be eliminated by introducing a second diode ''D_2'' in series with that. This will make the output identical if R<sub>1</sub> and R<sub>2</sub> are identical. See the image above. The corresponding simulation file is [[File:555 diodes2 300 300.circuitjs.txt]]. Adding one more resistance (or potentiometer) to make it more symmetric. This is discussed in more detailed in the next chapter, because the two potentiometers can be easily replaced by a one.

Mol: /* Method 2; Longer low time: Add a Diode */

2024-08-05T15:58:12Z

Method 2; Longer low time: Add a Diode

← Older revision		Revision as of 18:58, 5 August 2024
Line 5:		Line 5:
	555 diode Ranalysis.png\| The simulations.		555 diode Ranalysis.png\| The simulations.
	555 diode RanalysisContour.png\| The contour and surface plot of varying resistances.		555 diode RanalysisContour.png\| The contour and surface plot of varying resistances.
			Ic555 diode2 R.pdf\|Added the second diode. This will make the output identical if R<sub>1</sub> and R<sub>2</sub> are identical.
	</gallery>		</gallery>

Line 29:		Line 30:
	The simulation file: [[File:555 diode 300 300.circuitjs.txt]]		The simulation file: [[File:555 diode 300 300.circuitjs.txt]]

	The '''leakage current''' through ''R_2'' can be eliminated by introducing a second diode ''D_2'' in series with that. See the image above.		The '''leakage current''' through ''R_2'' can be eliminated by introducing a second diode ''D_2'' in series with that. This will make the output identical if R<sub>1</sub> and R<sub>2</sub> are identical. See the image above. The corresponding simulation file is [[File:555 diodes2 300 300.circuitjs.txt]].

Mol: /* Method 2; Longer low time: Add a Diode */

2024-08-05T12:20:35Z

Method 2; Longer low time: Add a Diode

← Older revision		Revision as of 15:20, 5 August 2024
Line 29:		Line 29:
	The simulation file: [[File:555 diode 300 300.circuitjs.txt]]		The simulation file: [[File:555 diode 300 300.circuitjs.txt]]

	The '''leakage current''' ~~throuh~~ ''R_2'' can be eliminated by introducing a second diode ''D_2'' in series with that. See the image above.		The '''leakage current''' through ''R_2'' can be eliminated by introducing a second diode ''D_2'' in series with that. See the image above.

Mol: /* Method 2; Longer low time: Add a Diode */

2024-08-05T12:20:18Z

Method 2; Longer low time: Add a Diode

← Older revision		Revision as of 15:20, 5 August 2024
Line 7:		Line 7:
	</gallery>		</gallery>

	The added diode ''D'' shorts the out the resistor ''R_2'' during the charging cycle; thus the capacitor charges directly from <math>R_1</math> removing ''R_2'', though a small leakage current will flow through it. The constants are modified due to the voltage drop of ''D''.		The added diode ''D'' shorts the out the resistor ''R_2'' during the charging cycle; thus the capacitor charges directly from <math>R_1</math> removing ''R_2'', though a small '''leakage current''' will flow through it. The constants are modified due to the voltage drop of ''D''.

	<math>		<math>
Line 29:		Line 29:
	The simulation file: [[File:555 diode 300 300.circuitjs.txt]]		The simulation file: [[File:555 diode 300 300.circuitjs.txt]]

	The leakage current throuh ''R_2'' can be eliminated by introducing a second diode ''D_2'' in series with that. See the image above.		The '''leakage current''' throuh ''R_2'' can be eliminated by introducing a second diode ''D_2'' in series with that. See the image above.

Mol: /* Method 2; Longer low time: Add a Diode */

2024-08-05T12:19:54Z

Method 2; Longer low time: Add a Diode

← Older revision		Revision as of 15:19, 5 August 2024
Line 7:		Line 7:
	</gallery>		</gallery>

	The added diode ~~<math>~~D~~</math>~~ shorts the out the resistor ~~<math>~~R_2~~</math>~~ during the charging cycle; thus the capacitor charges directly from <math>R_1</math> removing ~~<math>~~R_2~~</math>~~, though a small leakage current will flow through it. The constants are modified due to the voltage drop of ~~<math>~~D~~</math>~~.		The added diode ''D'' shorts the out the resistor ''R_2'' during the charging cycle; thus the capacitor charges directly from <math>R_1</math> removing ''R_2'', though a small leakage current will flow through it. The constants are modified due to the voltage drop of ''D''.

	<math>		<math>
Line 28:		Line 28:

	The simulation file: [[File:555 diode 300 300.circuitjs.txt]]		The simulation file: [[File:555 diode 300 300.circuitjs.txt]]

			The leakage current throuh ''R_2'' can be eliminated by introducing a second diode ''D_2'' in series with that. See the image above.

Mol: /* Method 2; Longer low time: Add a Diode */

2024-08-05T12:11:00Z

Method 2; Longer low time: Add a Diode

← Older revision		Revision as of 15:11, 5 August 2024
Line 4:		Line 4:
	Ic555 diode.pdf\| The schematics.		Ic555 diode.pdf\| The schematics.
	555 diode Ranalysis.png\| The simulations.		555 diode Ranalysis.png\| The simulations.
			555 diode RanalysisContour.png\| The contour and surface plot of varying resistances.
	</gallery>		</gallery>

Mol: /* Method 2; Longer low time: Add a Diode */

2024-08-05T11:54:36Z

Method 2; Longer low time: Add a Diode

← Older revision		Revision as of 14:54, 5 August 2024
Line 18:		Line 18:
	<math>		<math>
	pwm% = \frac{ T_\text{on} }{ T_\text{on} + T_\text{off}}		pwm% = \frac{ T_\text{on} }{ T_\text{on} + T_\text{off}}
	~~= \frac{0.8 R_1 C}{0.8 R_1 C + 0.7 R_2 C }~~
	= \frac{0.8 R_1 }{0.8 R_1 + 0.7 R_2 }		= \frac{0.8 R_1 }{0.8 R_1 + 0.7 R_2 }
	</math>		</math>

Mol: /* Method 2; Longer low time: Add a Diode */

2024-08-05T11:54:07Z

Method 2; Longer low time: Add a Diode

← Older revision		Revision as of 14:54, 5 August 2024
Line 24:		Line 24:
	which simplifies to		which simplifies to
	<math>		<math>
	pwm% =\approx \frac{R_1 }{R_1 + R_2 }		pwm% \approx \frac{R_1 }{R_1 + R_2 }
	</math>		</math>

	The simulation file: [[File:555 diode 300 300.circuitjs.txt]]		The simulation file: [[File:555 diode 300 300.circuitjs.txt]]

Mol: /* Method 2; Longer low time: Add a Diode */

2024-08-05T11:53:55Z

Method 2; Longer low time: Add a Diode

← Older revision		Revision as of 14:53, 5 August 2024
Line 20:		Line 20:
	= \frac{0.8 R_1 C}{0.8 R_1 C + 0.7 R_2 C }		= \frac{0.8 R_1 C}{0.8 R_1 C + 0.7 R_2 C }
	= \frac{0.8 R_1 }{0.8 R_1 + 0.7 R_2 }		= \frac{0.8 R_1 }{0.8 R_1 + 0.7 R_2 }
	~~\approx \frac{R_1 }{R_1 + R_2 }~~
	</math>		</math>

			which simplifies to
			<math>
			pwm% =\approx \frac{R_1 }{R_1 + R_2 }
			</math>

	The simulation file: [[File:555 diode 300 300.circuitjs.txt]]		The simulation file: [[File:555 diode 300 300.circuitjs.txt]]