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Parts explanation for Remote Door Lock


This is the remote engine starter equipment which is made by the BULLDOG SECURITY Inc..
The equipment can be worked by being remote using the radio.

NPN-type transistor (2SC1815)

This is the general NPN type transistor for small signal amplification.
You can use other transistor for small signal amplification with over 100mA Ic(Collector electric current).

Diode (1S1588)

This is the switching diode for the small signal.
This diode is used to protect a transistor from the back electromotive force of the relay. It's better to use the diode for the rectification when using a big relay.

Relay (G5A-237P)

This is the small relay which is made by the OMRON company. The drive voltage is DC 12V.
The size is 10mm of vertical, 15.6mm of the sides, the 7.5mm height.
As for the specification of the point of contact, the voltage is upto 60V and the current is upto 0.5A in the AC and the DC.
There is polarity in the coil of this relay. When connecting oppositely, the relay doesn't work.

Aluminum electrolytic capacitor

These capacitors are used for timer circuits. I used 16V 33uF. I had only two 16V type when I made this so I used a 25V type(The big one).
Because there is polarity in the lead wire of this capacitor, be careful so as not to make a mistake when mounting.


Because the big electric current doesn't flow at this equipment, I used the small resistor of 1/6 W.

Printed board

I used the universal printed board.
It is the boad with 15 holes x 25 holes.

Wiring terminal

This is a terminal for the wiring. You may wire to the printed board directly without terminal.
When using a thick wire, because the interval of the printed board and the case is narrow, it's easier to wire at the component side of the board.


I used the plastic case named TB-32 made by T.SIN Co. in Japan. The fixing stud which fits the board used this time is provided inside this case.


The big electric current didn't flow through this equipment but I used thick wires to prevent wire's cutting with the vibration.