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lennybogzy
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I need to drive some switches which require 28V and sink about 200ma of current. What's my cheapest option? build something or buy some dac?
Cheapest Option for Computer Driven Relays - Build or Buy?
- Thread starter lennybogzy
- Start date
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- Computer
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Discussion Overview
The discussion revolves around the best approach to drive switches requiring 28V and 200mA of current, exploring whether to build a solution using transistors or to purchase a digital-to-analog converter (DAC). The scope includes practical applications and circuit design considerations.
Discussion Character
- Technical explanation, Experimental/applied
Main Points Raised
- One participant inquires about the cheapest option to drive switches requiring 28V and 200mA.
- Another participant suggests using npn open collector transistors with specific voltage and current ratings, recommending components like the 2N2222A or TIP120, and notes they can be driven by a 5V source.
- A further contribution describes a circuit diagram for a relay driver, detailing the use of a resistor to limit current into the base of a power transistor and a diode to protect against voltage spikes from the relay coil.
- A later reply confirms that the simplest solution was to use a single 2N2222A transistor, which worked effectively for the participant's needs.
Areas of Agreement / Disagreement
Participants generally agree on the use of transistors for driving the switches, with multiple suggestions for specific components. However, there is no consensus on whether building a solution is definitively cheaper than buying a DAC, as the initial inquiry remains open-ended.
Contextual Notes
The discussion does not resolve the comparison between building and buying, and assumptions about cost-effectiveness and component availability are not explicitly stated.
Who May Find This Useful
Individuals interested in circuit design, particularly those looking for cost-effective solutions for driving relays or switches in electronic projects.