Multi-stage output delay circuit

The figure shows a delay circuit with multi-level output. The circuit uses an operational amplifier as a comparator. When the voltage VE is applied to the non-inverting input of the operational amplifier A1, the voltage VC1 at the non-inverting input of the operational amplifiers A2, A3, and A4 will rise along the exponential curve. The voltage provided by the graded voltage divider is added to the inverting input of the operational amplifier. Therefore, at the moments t1, t2, and t3 when the input of each operational amplifier changes from zero to VB (power supply voltage), each output signal is flipped, thereby achieving the purpose of step-by-step delay of VA1, VA2, and VA3. Note that this circuit uses dual power supplies, namely positive power supplies VE and VB and negative power supply -VB.