# 8.5. Circuit Schematic Builder Problem¶

In circuit schematic builder problems, students can arrange circuit elements such as voltage sources, capacitors, resistors, and MOSFETs on an interactive grid. They then submit a DC, AC, or transient analysis of their circuit to the system for grading.

## 8.5.1. Create a Circuit Schematic Builder Problem¶

1. In the unit where you want to create the problem, click Problem under Add New Component, and then click the Advanced tab.
2. Click Circuit Schematic Builder.
3. In the component that appears, click Edit.
4. In the component editor, replace the example code with your own code.
5. Click Save.

Problem Code

To create the problem in the image above, paste the following code into the Advanced Editor.

<problem>
<p>Make a voltage divider that splits the provided voltage evenly.</p>
<schematicresponse>
<center>
<schematic height="500" width="600" parts="g,r" analyses="dc"
initial_value="[["v",[168,144,0],{"value":"dc(1)","_json_":0},["1","0"]],["r",[296,120,0],{"r":"1","_json_":1},["1","output"]],["L",[296,168,3],{"label":"output","_json_":2},["output"]],["w",[296,216,168,216]],["w",[168,216,168,192]],["w",[168,144,168,120]],["w",[168,120,296,120]],["g",[168,216,0],{"_json_":7},["0"]],["view",-67.49999999999994,-78.49999999999994,1.6000000000000003,"50","10","1G",null,"100","1","1000"]]"
/>
</center>
<answer type="loncapa/python">
dc_value = "dc analysis not found"
for response in submission[0]:
if response[0] == 'dc':
for node in response[1:]:
dc_value = node['output']
if dc_value == .5:
correct = ['correct']
else:
correct = ['incorrect']
</answer>
</schematicresponse>
<schematicresponse>
<p>Make a high pass filter.</p>
<center>
<schematic height="500" width="600" parts="g,r,s,c" analyses="ac"
submit_analyses="{"ac":[["NodeA",1,9]]}"
initial_value="[["v",[160,152,0],{"name":"v1","value":"sin(0,1,1,0,0)","_json_":0},["1","0"]],["w",[160,200,240,200]],["g",[160,200,0],{"_json_":2},["0"]],["L",[240,152,3],{"label":"NodeA","_json_":3},["NodeA"]],["s",[240,152,0],{"color":"cyan","offset":"0","_json_":4},["NodeA"]],["view",64.55878906250004,54.114697265625054,2.5000000000000004,"50","10","1G",null,"100","1","1000"]]"/>
</center>
<answer type="loncapa/python">
ac_values = None
for response in submission[0]:
if response[0] == 'ac':
for node in response[1:]:
ac_values = node['NodeA']
print "the ac analysis value:", ac_values
if ac_values == None:
correct = ['incorrect']
elif ac_values[0][1] < ac_values[1][1]:
correct = ['correct']
else:
correct = ['incorrect']
</answer>
</schematicresponse>
<solution>
<div class="detailed-solution">
<p>Explanation</p>
<p>A voltage divider that evenly divides the input voltage can be formed with two identically valued resistors, with the sampled voltage taken in between the two.</p>
<p><img src="/c4x/edX/edX101/asset/images_voltage_divider.png"/></p>
<p>A simple high-pass filter without any further constaints can be formed by simply putting a resister in series with a capacitor. The actual values of the components do not really matter in order to meet the constraints of the problem.</p>
<p><img src="/c4x/edX/edX101/asset/images_high_pass_filter.png"/></p>
</div>
</solution>
</problem>