I am trying to add Diac component into my OrCAD v16.5 Schematic Layout. But, I only find this code below as a netlist. Even Though, I can't include the netlist into OrCAD Capture perfectly. It didn't worked. There is no Diac component in among OrCAD Capture libraries. I really searched too many times in web. The question is: How can I work with diacs in OrCAD Capture? The real Diacs are commonly named as: DB3, DB4, DB5, BR100, ER900. But there is nothing in OrCAD :(

.subckt diac 1 2 
*Based on BR100 measured data
*Convergence problems often occur with this model
*If you have a better model please tell me
Vdummy 1 5 dc 0
Ediac 5 2 TABLE {I(Vdummy)} = 
+ (-10.06m,-20.46) (-9m,-20.5)    (-7.02m,-20.72) (-5.98m,-20.89) 
+ (-5.05m, -21.11) (-3.26m,-21.91) (-2.15m,-22.96) (-1.6m,-23.99) 
+ (-7.2n,   -32.5) (-4.0n, -32) (-3.2n,-31) (-2.9n,-30) (-2.5n,-28.03) 
+ (-2.3n,-25.27) (-2n,-20.15) (-1.9n,-15) (-1.8n,-7.96) (-1.5n,-1.2) 
+ (0,0) (1.6n,1.24) (1.65n,5.15) (1.7n,7.91) (1.8n,10.1) (1.9n,15)  
+ (2.1n,20) (2.4n,25.28) (2.9n,28.26) (3.3n,30.5) (1.6m,23.21) (2.3m,22.16) 
+ (3.1m,21.44) (4.05m,20.99) (5.01m,20.65) (6.04m,20.32) 
+ (6.98m,20.14) (8.09m,20.02) (9.08m,20.02) (10.12m,19.91)  
.ends diac

2 Answers 2


I am trying to add Diac component into my OrCAD v16.5 Schematic Layout.

The subcircuit you listed is for doing simulations BUT you only want it to be a component in the schematic. Yes?

Find a component that looks like a diac (maybe an SCR or a diode) and place it somewhere on your schematic page. Right click the component and selct "edit part". This takes you to a new screen where you can edit the circuit symbol to be whatever shape you want - you can add pins, rename pins and totally redraw it to how you want it to look.

When done editing the part leave edit mode by pressing the X in the top right hand corner (as you would when closing down a sheet of a schematic).

OrCAD will then ask you if you want to update all parts - just select the option that says something like "only update this part" and hey presto you've edited a component and in your schematic it should look like a diac (or whatever you redrew).

  • \$\begingroup\$ Thank you for your help. I select 1N4376 diode >> I redraw it like Diac, but I couldn't assign the netlist into it. OrCAD said there is no library I have. Yes, it's true. I have only a part not library so far. Should I use 2 diodes and 2 DC voltage source to build up seem like a diac? Thank you! \$\endgroup\$
    – Bay
    Dec 23, 2013 at 19:40
  • \$\begingroup\$ @Bay - if you just want to draw a schematic forget about adding the netlist into it. If you want to run simulations from OrCAD I can't help you solve this problem, sorry. \$\endgroup\$
    – Andy aka
    Dec 23, 2013 at 19:58
  • \$\begingroup\$ @Bay If the absence of a library is keeping you from generating the netlist, you could copy the newly created DIAC symbol into a new symbol library. But then again, this might not help you to simulate the design. \$\endgroup\$
    – Avin
    Mar 3, 2014 at 14:16


General Diac Model

I asked my question and let me answer mine. Yes, there is no part like Diac in OrCAD. Maybe they didn't need this but I needed, so, I made an great working :)

The zeners voltage are about your choice to edit diac's VBO voltage. Diac's have got breakover voltage to work. I used thyristors and zeners to build up my diac. Now my VBO=28Volt approx. That's it :)


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