NE555 Square Wave Generator

The board boasts an NE555 timer chip configured in four frequency ranges,
1Hz to 50Hz(L jumper),
50Hz to 1kHz,
1kHz to 10kHz and
10kHz to 200kHz (H jumper)
all adjustable with an onboard jumper along with two trim-pots to adjust the output frequency and the duty cycle. Included onboard is an indicator LED indicator which illuminates on a low-level output and flashes relative to the output frequency. At higher frequencies, the LED will appear to be solid eventually dimmed (depending on duty cycle)

Size: 3.1CM * 2.2CM

Period T = 0.7 (RA +2 RB) C
RA, RB is 0-10K adjustable;
Low profile when C = 0.001UF;
IF stalls C = 0.1UF;
High-frequency file C = 1UF;
HF stalls C = 100UF