Redstone circuits/Clock/hopper clock

Hopper-Loop Clock

1×3×2 (6 block volume)
1-wide, flat, silent
clock output: 4 ticks on, 4 ticks off
clock period: 8 ticks

The left hopper contains 1 item.

N-Hopper-Loop Clock

2×(N/2+1)×2 (2×N+4 block volume)
flat, silent
clock output: 4 ticks on, 4×N-4 ticks off
clock period: 4×N ticks

The bottom-right hopper contains 1 item.

Ethonian Hopper Clock

2×6×2 (24 block volume)
flat
clock period: 8 ticks to 256 seconds (4m16s)

The right hopper contains multiple items.

Ethonian Hopper Clock
(1-Wide Compact)

1x6x3 (18 block volume)
1-wide

The right hopper contains multiple items.

Smallest hopper clock.

Ethonian Hopper Clock
(1-Wide Tileable)

1x8x3 (24 block volume)
1-wide, tileable

The right hopper contains multiple items.

Modified Ethonian Hopper Clock
(No sticky pistons)

1x8x3 (24 block volume)
1-wide, tileable

The right hopper contains multiple items.

Ethonian Hopper Clock
(1-Wide "Upside-Down")

1x8x3 (24 block volume)
1-wide

The right hopper contains multiple items.

RS NOR Latch Hopper Clock

4×6×2 (48 block volume)
flat, silent
clock period: 8 ticks to 256 seconds (4m16s)

The right hopper contains multiple items.

1-Wide RS NOR Latch Hopper Clock

1x7x5 (35 block volume)
1-wide, silent
clock period: 8 ticks to 256 seconds (4m16s)

The right hopper contains multiple items.

Hopper-Latch Hopper Clock
Level 1 (bottom layer)	Level 2 (top layer)
2×4×3 (24 block volume) silent clock period: 8 ticks to 256 seconds (4m16s) The top hopper in the bottom layer contains 1 item. The top hopper in the top layer contains multiple items.

SethBling's Hopper Clock

6×6×2 (72 block volume)
flat, silent
clock period: 1.6 seconds to 512 seconds (8 minutes, 32 seconds)

The top-left hopper contains multiple items.

SethBling's Hopper Clock (Simplified)

6×6×2 (72 block volume)
flat, silent
clock period: 1.6 seconds to 512 seconds (8 minutes, 32 seconds)

The top-left hopper contains multiple items.

SethBling's Hopper Clock ("Amputated")

2×6×2 (24 block volume)
flat, silent
clock period: 1.6 seconds to 256 seconds (4 minutes, 16 seconds)

The bottom-left hopper contains multiple items.

2-Stage MHDC

5×6×2 (60 block volume)
flat
clock period: up to 81.9 hours (3.4 real-life days)

The right hopper and right dropper contain multiple items.

2-Stage MHDC (without Sticky Pistons)
Q Level 1 (bottom layer)	Level 2 (top layer)
8x4x2 (64 block volume) 2 high, no sticky piston, multiplicative clock period: up to 81.9 hours (3.4 real-life days) The right hopper and right dropper contain multiple items. (This is a combination of the 2-Stage MHDC and the Modified Ethonian Hopper Clock)

2-Stage MHDC (Without Sticky Pistons, Compressed)

10x4x1 (40 block volume)
flat
clock period: up to 81.9 hours (3.4 real-life days)

The right hopper and right dropper contain multiple items.