RC oscillators and NAND multivibrators

[yeyeb]

nand oscillator

k i really need to know wat is going on in RC oscillators. i have seen in sites that this a simple circuit such as

**broken link removed**

is an oscillator but wen i try to connect an bulb it doesn't seem to blink around 1 Hz , taking resistor= 1k and capacitor= 100uF and the formula being Freq=1/(2pi*RC) . Also wen is the formula freq= 1/(3RC) used. I probably sound so noob but can someone explain y the circuit doesn't work.

Also about Astable Multivibrators using NAND circuit in that page

**broken link removed**

I really need to understand wat the heck is going on in that circuit. Lol can anyone also explain where the power source goes.

 

[LvW]

1/2pi*rc

An oscillator delivers some kind of energy. Where does it come from ?
Answer: Such a passive RC circuit as shown in the link has to be combined with an amplifier in order to work as an oscillator. This passive ladder has the task to produce at a certain frequency a phase shift of 180 deg. Combine it with an inverting amplifier (with the appropriate gain value) in a closed loop and you have 360 deg in total which satisfies the Barkhausen criterion.