Hi i am new here, i need the circuit of a triangle wave generator without using op amp for homework and i can t find one, everyone uses op amp, is here someone who has the circuit schematic? I can only use R,C,bipolar tranzistor/t-mos,diode, zener diode, no L.

 

Can it be sawtooth or does it have to be a triangle (equal positive and negative slope) waveform.

 

Hi i am new here, i need the circuit of a triangle wave generator without using op amp for homework and i can t find one, everyone uses op amp, is here someone who has the circuit schematic? I can only use R,C,bipolar tranzistor/t-mos,diode, zener diode, no L.

Hi,

Generally, the way that has been done for ages and ages is to use a constant current circuit (bipolar for example) and have it charge a capacitor. That creates a voltage ramp because v=i*t/C with 'i' constant and 't' the charge time. You then use some digital logic to get it to switch at regular intervales which may involve another circuit for the discharge. They even used this in black and white TV sets long time ago.
You can even fake it if you do not need absolute precision or a textbook theoretically ideal generator. That's because when a capacitor starts to charge through a resistor powered by a voltage supply, the initial ramp is almost linear up to maybe 1/2 to 1 time constant. That's an approximation to a ramp, and then you work out the discharge in a similar manner.

It sounds like you have to design it yourself though, so you have to look up first how to design a constant current circuit using one or more bipolar transistors. If an approximation is good enough, look up how a capacitor charges through a resistor fed from a constant voltage supply.

 

Get the datasheet of the ICL8038 where a simplified schematic shows how it works.

A late member of this forum even produced a simulation of the whole chip in LTSpice. I recall claiming that a search for any post of members that passed away is imposible using their nickname! They are ignored by the software, ridiculous as it is.

I experienced this when trying to look for exactly that simulation.

Will try to retrieve it from my laptop if you tell you are still interested.

 

it must be triangle waveform

 

Hi,

Generally, the way that has been done for ages and ages is to use a constant current circuit (bipolar for example) and have it charge a capacitor. That creates a voltage ramp because v=i*t/C with 'i' constant and 't' the charge time. You then use some digital logic to get it to switch at regular intervales which may involve another circuit for the discharge. They even used this in black and white TV sets long time ago.
You can even fake it if you do not need absolute precision or a textbook theoretically ideal generator. That's because when a capacitor starts to charge through a resistor powered by a voltage supply, the initial ramp is almost linear up to maybe 1/2 to 1 time constant. That's an approximation to a ramp, and then you work out the discharge in a similar manner.

It sounds like you have to design it yourself though, so you have to look up first how to design a constant current circuit using one or more bipolar transistors. If an approximation is good enough, look up how a capacitor charges through a resistor fed from a constant voltage supply.

Thank you for your reply, it was helpful.

 

Get the datasheet of the ICL8038 where a simplified schematic shows how it works.

A late member of this forum even produced a simulation of the whole chip in LTSpice. I recall claiming that a search for any post of members that passed away is imposible using their nickname! They are ignored by the software, ridiculous as it is.

I experienced this when trying to look for exactly that simulation.

Will try to retrieve it from my laptop if you tell you are still interested.

If you can retrieve it, it might help me a lot in this process, thank you!

 

If you can retrieve it, it might help me a lot in this process, thank you!

Go for the datasheet first. Simple as posting here.

 

We are not allowed to do your homework for you but we are allowed to help you with your understanding of the assignment and give you some hints if needed.

What is your idea for a good solution to this problem?

 

Old school signal generators often used "steering diodes" combined with current sources, this hint might get you going.

 

What is the p-p voltage required?

 

What is the p-p voltage required?

this is the range 2.4V-12V

 

We are not allowed to do your homework for you but we are allowed to help you with your understanding of the assignment and give you some hints if needed.

What is your idea for a good solution to this problem?
By using op amp the triangle waveform looks perfect, but in this simulation the line is not perfect

 

Go for the datasheet first. Simple as posting here.

i went for the datasheet at first but the simplified schematic circuit is not what i am looking for because i have to respect 40mmx40mm for pcb

 

i went for the datasheet at first but the simplified schematic circuit is not what i am looking for because i have to respect 40mmx40mm for pcb

Show a picture of what you tried and the schematic as well.

 

Can you post the text of the requirements you have been given instead of dropping them on us one by one?

 

le waveform looks perf

Show a picture of what you tried and the schematic as well.

 

Can you post the text of the requirements you have been given instead of dropping them on us one by one?

adjustable oscillation frequency in the range 2.4-48khz, output load 24kohm, control of the oscillation amplitude in the range 2.4-12V, the possibility of adjusting the up/down ramps of the triangular signal,operating temperature range 0-70

 

Hi,

Yikes, anything simpler perhaps?
How perfect does this have to be?

 

Hi,

Yikes, anything simpler perhaps?
How perfect does this have to be?

Hi, i need to respect the above mentioned requirements