Hi there,
I would like some help designing a 555 timer astable circuit that has a flip time of up to 5 mins (Period 10mins) and a mark to space ratio of exactly 50%. I have built three versions based on circuits from contacts and websites and they all are not quite right when it comes to measuring the parameters.
I have shown the three I have used so far in the three attached graphics. No 1 I could not get to work at all, No 2 can give me a good 120s period but the two states were not of equal duration and out by about 7 secs over that time. No 3 similarly can give me the long periods but is again not equal.
The circuit is used to switch between two banks of batteries so that they have equal discharge and charging times. Is there another circuit variation that will provide a period of 120-600s and equal durations of high and low?
I appreciate any thoughts,
Jules
![Option 3.jpeg Option 3.jpeg](https://forum.allaboutcircuits.com/data/attachments/153/153104-b7f7c12a9fa36a277bbaa5ab1e3d15d5.jpg)
I would like some help designing a 555 timer astable circuit that has a flip time of up to 5 mins (Period 10mins) and a mark to space ratio of exactly 50%. I have built three versions based on circuits from contacts and websites and they all are not quite right when it comes to measuring the parameters.
I have shown the three I have used so far in the three attached graphics. No 1 I could not get to work at all, No 2 can give me a good 120s period but the two states were not of equal duration and out by about 7 secs over that time. No 3 similarly can give me the long periods but is again not equal.
The circuit is used to switch between two banks of batteries so that they have equal discharge and charging times. Is there another circuit variation that will provide a period of 120-600s and equal durations of high and low?
I appreciate any thoughts,
Jules
![Option 1.jpeg Option 1.jpeg](https://forum.allaboutcircuits.com/data/attachments/153/153102-f2cf89980529c7db5d201af93fe56e22.jpg)
![Option 2.jpeg Option 2.jpeg](https://forum.allaboutcircuits.com/data/attachments/153/153103-d9891a9e2da0d82b3f854e7dcbed1fc4.jpg)
![Option 3.jpeg Option 3.jpeg](https://forum.allaboutcircuits.com/data/attachments/153/153104-b7f7c12a9fa36a277bbaa5ab1e3d15d5.jpg)