Ken Stone/1973 classic Serge/Serge peak and trough

The following info on the 1973 variant of the Peak and Trough module is presented for educational/historic purposes only and are not to scale.

How it works
Functionally it is remarkably simple. Diodes form the linear equivalent of an OR gate or an AND gate. There is a 0.6V voltage loss across the diodes. This is followed by a complementary emitter follower which loses 0.6 volts in the opposite direction, thus compensating for the loss in the diodes. A constant current source acts as a pull-up or pull-down for the emitter follower. The "no inputs" base state is derived from a resistor pull-up or pull down to an appropriate voltage rail, while using another diode to clamp it to either 6 volts (trough) or 0 volts (peak). FD6666 diodes were used, though any common silicon signal diode would do. Generic general purpose silicon signal transistors can be substituted.

Construction
PCB connections:
 * A = Peak input
 * C = Peak input
 * B = Peak input
 * D = Peak input
 * E = Peak output
 * F = Trough input
 * G = Trough input
 * H = Trough input
 * I = Trough input
 * J = Trough output
 * W = 0v
 * X = +12v
 * Y = +6v
 * Z = -12v

CC-BY-NC
Readers are permitted to construct these circuits for their own personal use only. Serge Tcherepnin retains all rights to his work.