Location of pin #1 of NE555P chip

[audioguru]

Your schematic does not show a power supply voltage and does not show the speaker impedance. Then we cannot calculate if the 555 is overloaded and will blow up.

No, I get it. There is no loudspeaker, instead it is a DC piezo beeper. The 555 does not oscillate and is not a timer, instead it is a simple little transistor.

 

[fixit7]

Got it.

 

[fixit7]

Your schematic does not show a power supply voltage and does not show the speaker impedance. Then we cannot calculate if the 555 is overloaded and will blow up.

No, I get it. There is no loudspeaker, instead it is a DC piezo beeper. The 555 does not oscillate and is not a timer, instead it is a simple little transistor.

I updated my post to show the updated schematic showing Vcc and Piezo Speaker info.

 

[Pommie]

If yours has a half circle on a short end, pin 1 is on the side to the left of the half circle.

This is ambiguous and only correct if the semicircle is at the top.

Mike.

 

[audioguru]

The simple circuit does not need a 555 IC that uses battery power all the time even when it is reset. An ordinary little transistor can be used to turn the beeper on and when it turns off the beeper then uses no battery power.

 

[fixit7]

I am using a 9 volt power supply instead of a battery.

 

[fixit7]

Your schematic does not show a power supply voltage and does not show the speaker impedance. Then we cannot calculate if the 555 is overloaded and will blow up.

No, I get it. There is no loudspeaker, instead it is a DC piezo beeper. The 555 does not oscillate and is not a timer, instead it is a simple little transistor.

Texas Instrument data sheets says it's a timer.


• These devices are precision timing circuits capable of
producing accurate time delays or oscillation.

 

[audioguru]

Your circuit uses the 555 IC as a simple on-off transistor, not as a timer and not as an oscillator.