output voltage drop of 555 timer ic - Electronic Circuits Projects Diagrams Free

mozikluv · 11th November 2003, 06:14 AM

hi,

i have another question about the famous 555 timer, is the output voltage of pin 3 always about 2v lower than the supply voltage?

thanx

laroche73 · 11th November 2003, 01:00 PM

The 555 uses a bipolar totem-pole output. If you want rail-to-rail output swings, you might try using the CMOS version, the 7555 or mc1455. The CMOS version has a much lower drive capability, though. The output only swings close to the supply rails if you're driving one or two TTL loads.

mozikluv · 15th November 2003, 12:18 AM

hi laroche 73,

thanx for your informative reply, would you care to show the circuit of this bipolars, how they are connected and how they are used?

thanx

laroche73 · 15th November 2003, 01:29 PM

This link shows the internals of the 555, along with the theory of operation and a fairly detailed description of each pins' operation. (Q20 - Q24 make up the output stage).

http://www.electronics.dit.ie/staff/...55%20timer.htm

mozikluv · 18th November 2003, 02:48 AM

hi laroche 73,

thanx, thats the thing i have been looking

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

11th November 2003, 06:14 AM	(permalink)
mozikluv	output voltage drop of 555 timer ic hi, i have another question about the famous 555 timer, is the output voltage of pin 3 always about 2v lower than the supply voltage? thanx __________________ \"NONE BUT THE BRAVE DESERVES THE FAIR\" ~Shakespeare~

11th November 2003, 01:00 PM	(permalink)
laroche73	555 output The 555 uses a bipolar totem-pole output. If you want rail-to-rail output swings, you might try using the CMOS version, the 7555 or mc1455. The CMOS version has a much lower drive capability, though. The output only swings close to the supply rails if you're driving one or two TTL loads.

15th November 2003, 12:18 AM	(permalink)
mozikluv	bipolar totem pole circuit hi laroche 73, thanx for your informative reply, would you care to show the circuit of this bipolars, how they are connected and how they are used? thanx __________________ \"NONE BUT THE BRAVE DESERVES THE FAIR\" ~Shakespeare~

15th November 2003, 01:29 PM	(permalink)
laroche73	555 output stage This link shows the internals of the 555, along with the theory of operation and a fairly detailed description of each pins' operation. (Q20 - Q24 make up the output stage). http://www.electronics.dit.ie/staff/...55%20timer.htm

18th November 2003, 02:48 AM	(permalink)
mozikluv	555 innards hi laroche 73, thanx, thats the thing i have been looking __________________ \"NONE BUT THE BRAVE DESERVES THE FAIR\" ~Shakespeare~