simple TTL squarewave generator

The design of this squarewave generator is identical to that of the circuit described above, with the exception that it employs an IC from the increasingly popular Low Power Schottky (LS) TTL series, rather than a conventional TTL IC. Since the electrical characteristics of LS TTL devices differ from those of standard TTL ICs, the relationship between the oscillator frequency and the values of R and C will also be difficult, ·.vhilst an extra resistor is required for the circuit to function satisfactorily.