Oscillator using inverter

[koushikr_in]

inverter oscillator

we know that an oscillator can be formed using odd num of inverters(NOT gates) connected as a loop.


If we take one NOT gate and connect its output ot its input, will it act as an oscillator?
please give the reasons also?

 

[brmadhukar]

74ls04 oscillator

hi,
yes. it oscillates wit period equal to 2*propgation delay. how will you observe it?

it is difficult and also the waveform will not be really square.

B R M

 

[jorgito]

not gate oscillator

Hello,
An ideal not gate with non zero propagation delay will oscillate with 2*PropDelayTime, but I think that a real not gate will end stucked at the middle of the transfer function and will not oscillate at all. Please correct me if I'm wrong.
Best regards

 

[flatulent]

oscillator inverter

You will need some external delay network. Otherwise the inverter is so slow compared to the resistive feedback that it will come to quiescent in the linear region. This was done in the past to make linear amplifiers.

 

[dumbfrog]

74ls14 oscillator

:lol: oscillation happens when gain >1 and -180 additional shift

:lol: you have <1 gain and 0 shift

 

[djalli]

oscillator using inverter

we know that an oscillator can be formed using odd num of inverters(NOT gates) connected as a loop.


If we take one NOT gate and connect its output ot its input, will it act as an oscillator?
please give the reasons also?

See this oscillator below in picture uses 74LS04. It produces an oscillation for 4Khz.

have fun.

 

[echo47]

oscillator with inverter

An inverter with input hysteresis, such as 74LS14, will oscillate all by itself at many MHz. You can slow it down by adding an external RC delay network.

 

[djalli]

rc oscillator inverter

An inverter with input hysteresis, such as 74LS14, will oscillate all by itself at many MHz. You can slow it down by adding an external RC delay network.

I must add something also here to clear something out. You are absolutely correct echo47. You add RC networks to delay oscillation caused by the feedback you add (principle of oscillators) or hysterisis (again it is feedback indeed but the IC is said to exibit feedback or hysterisis). Call it whatever you like.

It will precisely oscillate up to its MAXIMUM practical bandwidth. For that you see the datasheet which most likely will give a ball park figure of this bandwidth.

 

[tbong27]

oscillators using not gates

Hi all, sorry to dig up an old post. I've been reading some papers regarding oscillators using inverters and my weak background in electronics is making me unable to understand the concepts



This is from a paper by George Lewis about an impedance analyser. First of all what does the resistor and capacitors do? reading from previous post it provides some sort of an external delay for the inverter? And the selected component values are just solely dependent on the oscillating frequency? And the frequency is calculated using 1/2*pi*R*C . This formula agrees for the 4khz needed in the paper. Is there anything else i need to know to explain this type of oscillator?

Thanks

Regards
Thompson

 

[FvM]

rc inverter oscillator

You should see it as a kind of astable multivibrator. For an exact frequency calculation, you have to know the output voltages and input thresholds of the involved ICs.