What single mark distinguishes connected from crossing wires?
Which battery terminal is the long line?
Series resistors: same current or same voltage?
What law does a resistor symbol always obey?
What does a junction dot on crossing wires mean?
The two wires are electrically connected (one node); no dot = they cross without touching.
Which battery terminal is the long thin line?
The positive (+) terminal.
A resistor symbol obeys which law?
Ohm's law, V=IR.
What does the ground symbol represent electrically?
The 0 V reference node; all voltages are measured relative to it.
In a series arrangement, what is shared by all components?
The same current.
In a parallel arrangement, what is shared?
The same voltage across each branch.
Which way must an LED/diode triangle point relative to current?
In the direction of conventional current flow (+ to −); it conducts one way only.
Formula for equivalent resistance of two parallel resistors?
1/Req=1/R1+1/R2.
What is a "node" in a schematic?
A set of points joined by unbroken wire, all at the same potential.
Why is a schematic not a physical picture?
It encodes topology (connections) and function, not shape/size/layout.
An open switch does what to its node?
Breaks it — no current can flow (open circuit).
What does a capacitor do to steady DC current?
Blocks it after charging (Q=CV; no continuous DC flow).
Recall Feynman: explain to a 12-year-old
A circuit diagram is like a subway map. It doesn't show the real bendy tunnels or how deep
they go — it just shows which stations connect to which. The little pictures are the "stations":
a battery is the pump that pushes the electric water, a resistor is a narrow pipe that
slows the water, an LED is a one-way gate that lights up when water goes the right way, and a
dot where lines meet means "these pipes are joined." No dot where lines cross? They just pass
over each other, like one road bridging over another. Read it by starting at the battery's + and
walking the whole loop back to the −.
Dekho, ek circuit schematic asli photo nahi hai — ye ek map hai jo sirf batata hai ki kaun sa
terminal kis se juda hai aur har component ka kaam kya hai. Component ka shape ya size matter
nahi karta; matter karta hai topology (kaun kis se connected hai) aur function (voltage/current
pe kya asar). Isiliye ek chhota sa zigzag "resistor" hai jo Ohm ka law V=IR follow karta hai, aur do
lambi-chhoti parallel lines "battery" hain jisme lambi line positive hoti hai.
Sabse important 80/20 trick: bas 5-6 symbols yaad kar lo — battery, resistor, capacitor, switch,
ground, aur diode/LED — to almost har basic circuit padh loge. Circuit padhne ka tarika simple hai:
battery ke + se shuru karo, wire ko follow karte hue poore loop mein ghoomo, aur wapas − pe aao.
Series mein current same rehta hai, parallel mein voltage same rehta hai — ye rule shape se hi pata
chal jata hai.
Ek cheez pe hamesha dhyaan do: jahan do wires cross karti hain, agar wahan dot (junction) hai tabhi
wo actually connected hain. Dot nahi hai to wo bas ek dusre ke upar se guzar rahi hain, connected nahi.
Yahi ek chhoti galti pura circuit ka matlab badal deti hai — short ya open bana deti hai. Toh yaad rakho:
"Dot matlab juda, bina dot matlab bas cross." Ground ka darr mat khao — ye sirf 0 V ka reference
point hai jiske relative baaki sab voltages measure hote hain.
