Symbol & function

Thread Starter

car enthusiast

Joined Feb 16, 2022
19
What is the attached symbol? Large letter N (equal spacing N, not additional zigzagging) with 1 line in and 1 line out, centered left and right on the N ... and NO contact points on the symbol. (Sorry to ask, just haven't been able to find it on the i'net ...)

The symbol is printed (on the circuit board) under a vertically-mounted 2-pin circular device 5/8" in diameter and slightly greater than 1/16" thick, black in color with enamel-like (somewhat-shiny) coating. It is the first device in (connected) from the Ignition switch ON signal pin (on a car circuit board). After the device, the circuit continues with serialized traces to 5 other types of capacitors, including 3 electrolytic ones, each feeding off elsewhere.

Given its location in the circuit, what is the attached symbol doing? Function-wise.

I'm also going to post a related question in the datasheets subforum.

Thanks!symbol.jpg
 

Thread Starter

car enthusiast

Joined Feb 16, 2022
19
Thanks! Your link is exactly what the printed symbol looks like, and it makes perfect sense ... now.

The only letters I could make out on it were an "M" inside a circle (kinda like Motorola's logo but not certain) followed by a 2 and then perhaps other digits
and then on the next line
K27 <can't make out what follows the 7 nor if its 1 or 2 digits)
and then under that
95 <with a leading dot centered on the 9 and trailing dot centered after the 5.
 

Thread Starter

car enthusiast

Joined Feb 16, 2022
19
Sure, here ya go. Note the "Max" next to the varistor and the "Min" next to the green capacitor. The cap is the next device along the trace immediately after the varistor.

What are the max and MIN in particular indicating, circuit-wise, coming off the Ign sw ON power input?

Oh, and can you tell if the Q86 (to the right of green cap) is a MOSFET or more typical darlington transistor? It connects to the MCU for the cruise control actuator's MOTOR circuit.

Thanks.
varistor pic for forum.jpg
 

wraujr

Joined Jun 28, 2022
40
Many times power input pins are located at ends of connectors.
And, you mention Ignition ON (i.e. 12VDC) and this is an auto application.
Power inputs (especially in a car) would need various "protection" devices for surge and overvoltage.
Both components look like these types of devices.
 

wraujr

Joined Jun 28, 2022
40
Is that an ODB2 connector? if so then there would also be protection devices to handle ESD, etc.
EDIT - Never mind I see later you said its a cruise control computer.
 
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