A compact an inexpensive module that contains two sample and hold circuits (which can be switched to track and hold behavior.)

Sample and holds are one of the more useful utilities in a system!  When triggered, they read (ie take a sample of) the current level of the input voltage and output (hold) that voltage until the next trigger - they essentially turn smooth voltage into stepped voltage!  Feed a white noise and trigger to get random values, feed a sequence and it's rhythm to a sample and hold to have the pitch hold through the rests.  Feed audio and clock with an audio rate square wave for sample rate reduction.  Sample and holds are super fun!   

Track and hold behavior (where high gate allows voltage to pass and voltage is held when the gate goes low) can be selected via jumper on the back.  Track and holds can be used to create canon type sequences and more.

Per Doepfer:

Module A-148 (Dual S&H) has two identical sample & hold modules, designed to produce 'staircase' voltages. The signal present at the sample input is sampled at a rate set by the signal at the trigger input, and held at that voltage at the S&H output.
The exact shape of the staircase depends on the sort of waveform at the sample input: NOISE or RANDOM signals produce random patterns; an LFO produces rising or falling staircase patterns.
Two LEDs for each S&H indicate the voltage (positive or negative) of the sampled signal.

Specifications:

4Hp

40mm Depth

20mA +12v

20mA -12v