3 stage time delay trigger circuit using 555 (or any other suggestion)

Hi!

I am nt very familiar with electronics design. Just have some basic knowledge. For one of our projects to heat an alloy with capacitive discharge current being controlled by SCRs, i need to make a 3 stage time delay trigger circuit using 555 ics(or any other suggestions?). Could anyone guide me doing that. There are 3 numbers of capacitors being discharged using 3 thyristors so i need to trigger 3 thyrsitors for one shot only. Th di/dt rsise of the anode current will be very high of the order of 250A/us so the gate triggering pulse should be of about 2.5 Amps for about 5ms. The gate cathode voltage should be arnd 20 V. These high output ratings are also a problem i guess. Any help in this regard will be appreciated.


Thanx
Ravi

ravi2024 said:

Hi!

I am nt very familiar with electronics design. Just have some basic knowledge. For one of our projects to heat an alloy with capacitive discharge current being controlled by SCRs, i need to make a 3 stage time delay trigger circuit using 555 ics(or any other suggestions?). Could anyone guide me doing that. There are 3 numbers of capacitors being discharged using 3 thyristors so i need to trigger 3 thyrsitors for one shot only. Th di/dt rsise of the anode current will be very high of the order of 250A/us so the gate triggering pulse should be of about 2.5 Amps for about 5ms. The gate cathode voltage should be arnd 20 V. These high output ratings are also a problem i guess. Any help in this regard will be appreciated.


Thanx
Ravi

Click to expand...

If you are not familiar with electronics, this sounds like a particularly dangerous first project. Use of SCRs/thyristors, discharging large capacitors, currents of around 250A.

See this circuit maybe you will find something usefull for you :

Three Stage - Cycling Timer Circuit
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Two Stage Time Delay Circuit
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Best regards,
Peter