Circuit Examples

Sample circuits to get you started

Economics & System Dynamics Models

CircuitJS1 includes specialized components for economic modeling using stock-flow analysis. These models demonstrate the application of system dynamics to monetary economics and accounting.

BOMD (Bank Originated Money and Debt) Model

A comprehensive model of bank lending and money creation in a simplified economy.

File: econ_BOMD.txt Load Model

Components:
- Banks Table (with Reserves, Debt to Savers/Borrowers, Equity)
- Borrowers Table (Borrowers Debt and Equity)
- Savers Table (Savings and Equity)
- Mathematical elements (Multipliers, Adders)
- Percent/Ratio meters for analysis

Key Features: - Three-sector economy: Banks, Borrowers, Savers - Lending dynamics with interest payments - Bank spending and money velocity - Accounting equation: Assets = Liabilities + Equity - Stock-flow consistency

Learning Objectives: - Understand endogenous money creation - Track money flows between sectors - Observe stock-flow accounting principles - Analyze interest rate effects on debt dynamics

Key Parameters: - Interest Rate: 5% (configurable) - Lending Fraction: 2% of GDP (configurable) - Velocity: 0.5 (money circulation speed) - Bank Spend Rate: 10% (how fast banks spend reserves) - Fee Rate: 0.5 (transaction fees)

BOMD Simple Model

A simplified version focusing on core banking operations.

File: econ_BOMDSimple.txt Load Model

Components:
- Banks Table (Loans, Deposits, Equity)
- Non-Bank Private Sector Table (Deposits, Loans, Equity)
- Differentiator for GDP calculation
- Divider for velocity computation

Simplified Focus: - Two-sector model: Banks and Private Sector - Direct lending relationship - GDP derived from money velocity (M×V) - Credit creation through bank loans

Key Concepts: - Bank credit creates deposits - Loans create deposits (not vice versa) - GDP = Money Supply × Velocity - Balance sheet symmetry between sectors

Use Cases: - Teaching basic banking operations - Understanding credit money creation - Observing GDP-debt relationships - Analyzing velocity effects

BOMD with Government

Extended model including government sector and central bank operations.

File: econ_BOMDwithGovt.txt

Load Model

Components:
- Banks Table (7 columns: Reserves, Debt, Gov Bonds, etc.)
- Borrowers Table (with tax and government spending flows)
- Savers Table (with tax and government spending flows)
- Treasury Table (Government bonds and equity)
- The Fed Table (Central bank reserves and operations)

Extended Features: - Five-sector economy: Banks, Borrowers, Savers, Treasury, Federal Reserve - Government spending and taxation - Bond issuance and interest payments - Central bank reserve management - Complete sectoral accounting

Government Operations: - Tax collection from all sectors - Government spending (distribution configurable) - Bond sales to finance deficits - Interest payments on bonds - Central bank monetary operations

Advanced Concepts: - Fiscal policy effects on private sector - Government deficit = Private sector surplus - Bond market operations - Reserve management by central bank - Sectoral financial balances

Policy Experiments: - Adjust tax rates and observe sector balances - Change government spending levels - Modify bond interest rates - Analyze deficit spending effects

How to Load These Models

  1. From Circuit Files:
    • Download from: src/com/lushprojects/circuitjs1/public/circuits/econ_*.txt
    • Use File → Import in CircuitJS1
  2. From Web Interface:
    • Circuits > Ecomonics >
    • Click on the desired file
    • Circuit loads automatically
  3. Experiment & Modify:
    • Adjust interest rates and lending fractions
    • Change spending and tax rates
    • Add scope traces to monitor key variables
    • Export modified circuits for sharing

Understanding the Economics Elements

These models use specialized CircuitJS1 components:

  • Table Elements: Represent balance sheets with Assets, Liabilities, Equity
  • Godly Tables: Include integration for stock accumulation over time
  • Multipliers/Dividers: Calculate derived variables (interest, fees, ratios)
  • Adders/Subtractors: Compute net flows between accounts
  • Percent Meters: Display ratios and rates
  • Stop Time: Halt simulation at specific time points

Educational Applications

Undergraduate Economics: - Money and banking fundamentals - Stock-flow consistent modeling - Sectoral accounting principles

Graduate/Research: - Modern Monetary Theory (MMT) concepts - Post-Keynesian economics - Endogenous money dynamics - Fiscal-monetary policy interactions

Policy Analysis: - Government deficit effects - Interest rate impacts - Credit cycle dynamics - Debt sustainability


Basic Circuits