I am trying to understand a part of the schematic for a relay based multiplexer. Basically the relays are triggered by
RESET :continuous signal of 3.5VDC <voltage < 16 VDC holds device in an active state
CLOCK: on the transition from <1.5 V to >3.5V, relays advance on the leading edge of the clock; clock must be a minimum of 5 ms in width
I just want to understand what are the purpose of resistors,capacitor & diodes in this circuit. More specifically R1 & R3.
As far as I understand:
- R2& R4: pulldown resistors. Making sure that these inputs are not floating? BTW both connected to different pins of the same schmitt trigger IC.So why are the resistors values different?
- R1 & R3 in series to limit the current? Not sure about them? Also why different values again?
- C1 & C2 :decoupling capacitors to ensure smooth signal voltage levels?
- D1 & D2: 1.5KE20A transzorbs limiting clock & reset to 16V.This is pretty straightforward i think.