The second board in this initial batch of Dave's Digital Design Doohikey boards is a 4-bit Binary Ripple Counter based on the  popular 74HC93 chip. This board is pretty simple with just the chip and some bypass caps. Since I want these boards to be reusable and configurable, I added a series of jumpers to allow the end user to configure the counter with different modulus. The 74HC93 has a built in NAND gate that controls the reset of the chip. As an example if I wanted a modulus 10 counter, I would place a jumper on the 8A position, and a jumper on the 2B position. This would then cause a reset back to zero on the tenth count. This board would normally be used between other boards, so no barrel jack for power was included.