0
votes
1answer
49 views

How do I replace a CdS sensor in a circuit with an ALS replacement?

I am wanting to replace a resistor in a 555 circuit with a light sensor, but don't want to use the traditional CdS cell. I'd like to use an ALS such as the Everlight ALS-PDT144-6C/L451. This is the ...
1
vote
2answers
82 views

How can I maintain a fix voltage until my battery is almost dead?

I am experimenting with a simple circuit. I have an Arduino board, a proto-board and an IR sensor (that uses electricity from the Arduino board). I use a 9V battery to feed the Arduino. My problem ...
3
votes
4answers
748 views

Widely available IC for encording and Decoding DTMF data

I am planning to do some research in data transmission over the air. For this I am interested in DTMF encoding and decoding. Is there a widely available IC to achieve this? A circuit diagram using ...
0
votes
3answers
172 views

A device that wirelessly, securely posts to a server in response to door opening: off the shelf or custom-make?

I am looking for an off the shelf component for a project I am currently working on. Due to the nature of the project I cannot go into much detail about the project itself, only give a high level ...
-1
votes
2answers
171 views

Capacitors in RFID reader

I'm trying to understand a schematic of an RFID reader. Circuit: What capacitors are used - electrolytic or ceramic capacitors? I've seen schemes of RFID readers that use electrolytic capacitors, ...
0
votes
1answer
164 views

Can I change the input voltage for this temperature-controlled fan circuit:? [duplicate]

Possible Duplicate: Can this temperature-controlled fan circuit be modified for different input voltage? For the above temperature-controlled fan control circuit which is originally ...
2
votes
4answers
283 views

Why does conventional electricity flow out of + in a battery, but out of - in components?

It seems like when electricity flows out of + in a battery it should be attracted by a - end of a component, but it's not like that. Why?
3
votes
1answer
79 views

Is there a solution for keeping circuits with low frequencies small?

background I'm essentially making an mixed-signal/analog computer(to accelerate certain mathematical operations). I'm looking to create many AC filters (of different types) at low frequencies (sub ...
16
votes
3answers
976 views

What is this resistor for in this circuit?

I am studying electronics and I am currently reading/working my way through "Make: Electronics" by Charles Platt. Here is one of the circuit diagrams that he gives for making a basic burglar alarm: ...
1
vote
3answers
675 views

Where to buy an SR Latch [closed]

I am looking for a simple SR Latch. I'm new to electronics though and just doing a hobby project/teaching myself. Are SR Latches sold (I'm hoping to avoid building mine because I actually need at ...
1
vote
2answers
117 views

Looking for a USB/PCI controller that can replace a physical switch

I am looking for a component that I can drop into a circuit that will replace the functionality of a physical switch so that I can control it via computer, preferably via a standard interface (USB or ...