Circuit Project Electronic

This circuit designs to upward for divide by the frequency of a signal input , give down left just the half then to export come to the way output. Because of the transistor Q1 (BC549) bias stay the condition not active it then active get especial while signal input be positive volt only. [...]

U1 7555 is a CMOS version of 555 LM555 pdf datasheet.
The 555 here is in Astable Oscillator mode, C1 and C4 are decoupling capacitors 0.1uF value, ceramic disc.
The output is around 100kHz, If C3 is plastic or mica the frequency output will be stable with temperature. It is better to use a crystal oscillator.
The 555 [...]

A preamp that drives the CMOS counter input and a divide by 10 prescaler to extend the range of A Little More Serious Frequency Meter. The MCT10280 prescaler can be set to divide by 80, 40, 20, or 10, as a function of which pins are tied to the power supply. I set this one [...]