NE555 Pinout Diagram, 8-Pin Timer IC Pin Names and Functions

User question

what is the NE555 pinout diagram

Artificial Intelligence Response

Direct answer to the question

The NE555 is an 8-pin timer IC.
Its standard top-view pinout is:

 +---\/---+
GND 1 | | 8 VCC
TRIG 2 | NE555 | 7 DISCH
OUT 3 | | 6 THRESH
RESET 4 | | 5 CTRL
+-------+

Pin names

1. GND – Ground
2. TRIG – Trigger
3. OUT – Output
4. RESET – Active-low reset
5. CTRL – Control voltage
6. THRESH – Threshold
7. DISCH – Discharge
8. VCC – Positive supply

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Detailed problem analysis

How to read the diagram

• This is a top view of the IC package.
• If the notch or dot is facing upward, Pin 1 is at the top-left.
• Pin numbering proceeds counter-clockwise around the package.

Function of each pin

Pin	Name	Function
1	GND	0 V reference, negative supply
2	TRIG	Starts timing when voltage falls below about \(1/3 \, V_{CC}\)
3	OUT	Output signal from the timer
4	RESET	Forces output low when pulled low; usually tied to VCC if unused
5	CTRL	Access to internal control voltage; often bypassed to ground with 10 nF
6	THRESH	Ends timing when voltage rises above about \(2/3 \, V_{CC}\)
7	DISCH	Internal transistor discharges the timing capacitor
8	VCC	Positive power supply

Internal operating idea

The NE555 uses internal comparators and a flip-flop. Two key thresholds define its behavior:

\[ V{TRIG} \approx \frac{1}{3}V{CC} \]

\[ V{THRESH} \approx \frac{2}{3}V{CC} \]

• Pin 2 (TRIG) going below \(1/3 V_{CC}\) typically sets the output high.
• Pin 6 (THRESH) going above \(2/3 V_{CC}\) resets the output low.
• Pin 7 (DISCH) helps charge/discharge the external timing capacitor in monostable and astable circuits.

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Supporting explanations and details

Practical notes

• If RESET is not used, connect it to VCC.
• Place a 0.1 µF decoupling capacitor between VCC and GND close to the IC.
• If CTRL is unused, connect 10 nF from Pin 5 to GND to reduce noise sensitivity.

Common package note

The pinout is the same for standard DIP-8 and usually the same signal order for SOIC-8 versions of the 555 family.

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Practical guidelines

If you are wiring an NE555 on a breadboard, the minimum essential connections are:

• Pin 1 → Ground
• Pin 8 → Supply voltage
• Pin 4 → Tie to VCC
• Pin 5 → Optional 10 nF to GND
• Pins 2, 6, 7 → Connected according to monostable/astable design
• Pin 3 → Output to load or next stage

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Brief summary

The NE555 pinout is:

1 GND, 2 TRIG, 3 OUT, 4 RESET, 5 CTRL, 6 THRESH, 7 DISCH, 8 VCC

and the standard top-view diagram is:

 +---\/---+
GND 1 | | 8 VCC
TRIG 2 | NE555 | 7 DISCH
OUT 3 | | 6 THRESH
RESET 4 | | 5 CTRL
+-------+

If you want, I can also provide:

• the internal block diagram,
• an astable wiring diagram, or
• a monostable one-shot circuit using the NE555.

Disclaimer: The responses provided by artificial intelligence (language model) may be inaccurate and misleading. Elektroda is not responsible for the accuracy, reliability, or completeness of the presented information. All responses should be verified by the user.