Circuit symbols are used in circuit Symbols diagram which show how a circuit is connected together. The actual layout of the components is usually quite different from the circuit diagram. Circuit Symbols of Electronic ComponentsTo build a circuit you need a different diagram showing the layout of the parts on pcb.
Circuit Symbols of Electronic Components and two basic symbols were
a tunnel diode symbol looked like a pregnant piece of wire .basic symbols were heh … that’s what we called those spherical bead rectifiers .
in the diode department two basic symbols were used . the cathode was a skinny rectangular box . a filled in box stood for a power rectifier and an “empty” box meant a small signal diode (eg : 1N60)