**BUILD
TO UNDERSTAND CIRCUITS
**

(

**PART 1. IN THE KINGDOM OF ELECTRICITY (PASSIVE CIRCUITS)**

**Applying Ohm's Law ...**

**1. Voltage
Causes Current** in the most elementary 2-component voltage-controlled
electric circuit (a voltage source and a resistor).

General principle: *Difference causes movement*.

General building blocks: *pressurelike
source, impediment as a load*.

General atributes: *pressurelike, flowlike, impedimentlike*.

Electric principle: *Voltage
causes current*.

Electric building blocks: *ideal
voltage source, real (resistive, Ohmic) load*.

Electric variables: *voltage, current,
resistance*.

Building
blocks derived: *voltage-to-current converter, ideal current load*.

Applications: *battery
charger, current loop interface*.

**4. Measuring a Voltage
by a Current** in the circuit of a compound voltage load.

Building block composed: *compound
voltage load (voltage-to-current converter + ideal current load)*.

Applications: *compound
voltmeter (voltage-to-current converter + ammeter), **LED
indicator, transistor switch*.

**5. Resistance Determines
Current**. Resistance as an input in the 3-component
voltage-controlled electric circuit.

Building block derived: *resistance-to-current
converter*.

**6. Producing a Current by Varying a Resistance** in the circuit of a compound
resistance-controlled (RC)current source.

Building block composed: *resistance
controlled current source (constant voltage source + resistance-to-current
converter)*.

Applications: *rheostat,
DC motor current supply*.

**7. Measuring a Resistance
by a Current**.

Building blocks composed
(applications): *compound ohmmeter (constant voltage source + ammeter),resistive
sensors with current output (constant voltage source + resistance-to-current
converter + ammeter)*.

**8. Both Voltage and
Resistance Set Current** in the 3-component voltage-controlled
electric circuit.

Building block derived: *voltage-into-resistance
divider*.

Applications: *R/2R ladder
DAC with current output (principle)*.

**Reversing Ohm's Law ...**

**9. Current Causes
Voltage** in the Norton elementary 2-component electric circuit
(a current source and a resistor).

General principle: *Movement
causes difference*.

General building block: *flowlike
source*.

Electric principle: *Current
causes voltage*.

Electric building block: *ideal
current source*.

**10. Current Causes Voltage** in the more "complicated" 3-component
current-controlled electric circuit (the previous 2-component circuit enlarged
with an ideal voltage load).

Building
blocks derived: *current-to-voltage converter, ideal voltage load*.

**11. Producing a Voltage
from a Current** by the circuit of a current-controlled
voltage source.

Building
block composed: *current controlled voltage source (ideal current source
+ current-to-voltage converter)*.

**12. Measuring a Current
by a Voltage** in the circuit of a compound current load.

Building block composed: *compound
current load (current-to-voltage converter + ideal voltage load)*.

Applications: *compound
ammeter (current-to-voltage converter + voltmeter), **current
sensing, current feedback* etc.

**13. Resistance Determines
Current**. Resistance as an input in the 3-component
current-controlled electric circuit.

Building block derived: resistance-to-voltage converter.

**14. Producing a
Voltage by Varying a Resistance** in the circuit of a compound
resistance-controlled voltage source.

Building block composed: *resistance
controlled voltage source (constant current source + resistance-to-voltage
converter)*.

**15. Measuring a Resistance
by a Voltage**.

Building blocks composed
(applications): *compound ohmmeter (constant current source + voltmeter),
resistive sensors with voltage output (constant current source + resistance-to-voltage
converter + voltmeter)*.

**16. Both Current
and Resistance Set Voltage** in the 3-component current-controlled
electric circuit.

Building block derived: *current-by-resistance
multiplier*.

Applications: *R/2R ladder
DAC with voltage output (principle)*.

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To be continued