pulse generator - with variable pulse rate and pulse width

with variable pulse rate and pulse width The generator presented is based on two 555-timer ICs and provides rec- tangular pulse trains (waves) of which the pulse width and the pulse rate are variable. The first timer, IC1, is connected as an astable square-wave generator. Symmetry of waveform is maintained to within a few per cent by a stereo potentiometer and two diodes. Bear in mind that a square wave, by definition, is a rectangular wave with a 50 per cent duty factor, that is, its pulse width must be equal to half the pulse spacing. The frequency range is determined by switch- selective capacitors: with values as shown, it lies between 1 Hz and 100 kHz. Maximum output current of IC1 is 100 mA. The trailing edge of the output pulses from IC1 is used to trigger the second 555 which is connected as a monostable. This stage enables the pulse width to be varied between 10 IAs and 100 ms by switch-selective capacitors. Maximum output current of IC2 is also 100 mA. Switches, potentio...