RFC-1 Accessories and Miscellaneous Circuits page 4.5
4.2.2.1 Rising Edge Detection Circuit
74HC123AN retriggerable timer IC
0.1µF 50V monolithic ceramic capacitor*
5K Ohm ¼ W carbon film resistor*
1M Ohm ¼ W carbon film resistor
5VDC regulated power supply
Figure 4.3; Circuit to detect and extend a rising edge pulse
4.2.2.2 Falling Edge Detection Circuit
74HC123AN retriggerable timer IC
0.1µF 50V monolithic ceramic capacitor*
5K Ohm ¼ W carbon film resistor*
1M Ohm ¼ W carbon film resistor
5VDC regulated power supply
Figure 4.4; Circuit to detect and extend a falling edge pulse