logic gate equivalent circuit of a bosch relay?

thingmaker3

Joined May 16, 2005
5,084
The Bosh is what we call a "form C" relay or "Single Pole Double Throw" relay.

One can make logic gates from relays. Making a relay from a logic gate would be sort of like making a coldcut from a sandwich.

Are you perhaps looking for a solid state relay?
 

Thread Starter

03GTS

Joined Jan 5, 2007
12
The Bosh is what we call a "form C" relay or "Single Pole Double Throw" relay.

One can make logic gates from relays. Making a relay from a logic gate would be sort of like making a coldcut from a sandwich.

Are you perhaps looking for a solid state relay?

well what i am doing is making sequential turn signals. the problem is if i have the parking/running lights on and i turn my turn signal on that the leds need flash and not just stay on as running lights.

having problem cordinating both :)

solid state relays are expensive i am hoping i dont have to go that route :(
 

wireaddict

Joined Nov 1, 2006
133
This doesn't show the internal workings of the relay. A "C" form relay has one or more sets of contacts, each set with three terminals, a normally open [NO] & a normally closed [NC] contact wired in series with a common terminal connected to the junction between them. My guess is that wires #85 & 86 are the coil leads, wire #30 goes to the common, #87a to the NC & #87 to the NO contact.

I'm not familiar with the wiring on newer cars but the older ones had bulbs with two filaments or more than one bulb, one for the parking/running lights & the other, brighter one for turn signals & brake lights [on the rear]. Hopefully you have two sets of LEDs or have the space to add them.

As for operating the sequential turn signals you can use either a stepping relay or a shift register & LED driver transistors. To save some time & money you might cruise a few auto salvage yards & see what's there.
 

thingmaker3

Joined May 16, 2005
5,084
Schematic of the Bosch relay as used in this application:
bosch seq lights.jpg

Schematic of solid state circuit which should accomplish same thing:
mosfet seq lights sch.jpg
Select Q1 and Q2 to handle not less than 120% of the expected current and not less than 120% of B+.

Select R2 and R4 as not less than (120% of B+ voltage divided by 0.8 Amps.)

Select R1 and R2 as not less than (120% of "Turn Signal Active" voltage divided by 0.2 Amps.)
 
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