4026

7-segment display decade counter

Bit of a silly one.

The 4026 CMOS IC was designed for use in clocks and other appliances/equipment using 7-segment displays that only need to count upwards from 0-9. They can be chained together to get more digits, and with a slightly more complicated circuit you can make counters that reset on 60 for clocks/timers.

This eurorack module gives you 1 gate output for each segment and 1 gate output for the ÷10 count.
The result is 8 hardwired 10-step patterns, few of which are particularly musical.

I originally planned to just make a few kits for the WAMod synth DIY workshop here in Perth but I enjoyed it more than I expected so figured I might as well release it.
It can be fun when patched with LFOs, other counters, logic etc. to break up the otherwise monotonous patterns of the 0-9 count.

On the rising edge of the CLOCK input the internal binary counter advances by 1 and the count is decoded into the right combination of outputs to drive a standard old-fashioned 7-segment display.
NOTE: this CLOCK input circuit works best with square waves/triggers at frequencies less than a few Hz but if faster than that it can be any signal in your synth that crosses approx. 1V, up to at least 10kHz or so.

The RESET input is triggered on the rising edge of any signal that crosses approx. 0.5V and takes the count immediately back to 0 at any time.

A +ve signal applied to INHIBIT masks/ignores incoming clock pulses, pausing the count until Inhibit goes low again.

DISPLAY ENABLE is normally held high with nothing patched in. When patched, the current active display outputs will blink on and off with this input signal. Counting and resets will carry on unaffected by this input.
I like to send a steady rhythm/pattern to this input and have an irregular or less frequent signal on CLOCK to get gated rhythms on the segment outputs, for example.

The display outputs a-g are arranged on the panel in a mock 7-segment display, each light up segment/label corresponds to the jack directly below it.
The ÷10 output is high for counts 0-4 and goes low for counts 5-9.

6HP +12V: 10mA -12V: 0mA

http://isaacbeers.square.site/4026