The original is here. I have it translated, slightly modified and added their links and comments. First of all, the question arises: "What is it?" . Very simple. When using GPS, and playing MP3 files, it is desirable to connect the PDA to the onboard network, since the duration of the trip the battery may not be enough. Thus, in the car's cigarette lighter have a 12V (16A max). For Casio, we need to get 5V. The adapter is made on the basis of standard passive voltage regulator 7805 (PDF), the approximate cost of $ 0.35 in Moscow. You can use the domestic analogue - KR142EN5A (in common "KREN5A). Additionally, we need: an adapter for the cigarette lighter (the most expensive part of this set), a radiator for the stabilizer, the plastic box for mounting plug for connecting to Casio (power plug 4.0mmx1.7mm), fuse 2A, wires, insulating tubes.
Standard wiring diagram is shown in Figure 1.
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| Figure 1 |
For the insurance of "fool" in the input circuit can be added to fuse 2A (the original was used for the cigarette lighter adapter with built-in fuse 2A).
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| Figure 2 |
In the above article, the adapter is going to a simplified scheme, without smoothing capacitors (see Figure 3).
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| Fig.3 |
Connect the negative (external) output cigarette lighter adapter to the central (3) concluded 7805. Good (internal) output fluster found input (1) (for reliability it is desirable to use a fuse 2A and condenser). Negative (external) output connectors for Casio just fluster the central (3) concluded 7805. Good (internal) output fluster concluded output (2) (preferably using the capacitor). All carefully isolate. Stabilizer screws to a suitable heat sink (for better heat transfer using thermal paste).For better cooling radiator is necessary to take more!
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All farming is going in a plastic box of suitable size (eg, a bar of soap). For better cooling box more desirable. If, after the assembly of the stabilizer is strongly heated, the plastic box you can drill a hole, but it is better to take the radiator with a larger area of dispersal! Now you need to check the correctness of the assembly, connect the adapter to the cigarette lighter to check the output voltage and polarity. WARNING! Before you connect the Casio, do not forget to check the polarity and the voltage at the output of the adapter! All adapter is ready!
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During operation, the stabilizer is extremely hot. It becomes very hot when charging the battery. Batteries of this adapter charges a little longer, as the charge current is less than the regular power supply. If the current exceeds 1A or stabilizer overheats, it automatically locks. Stabilizer automatically restarts! If the lamp is lit Casio charge for too long - you need a larger radiator! Almost immediately after the publication of the above material, I received a letter from Oleg Maltsev: I did for the E11 power supply for 7805, just before her stands a bridge and three Conder. This thing is powered by anything (car, battery pack, transformer, power supply from the modem, etc. ...), does not require polarity, is placed in the cradle and operated for over 6 months. There. I naturally became interested and asked Oleg to describe the device in more detail. He sent me an interesting stuff that you and I propose.
Nutrition PPC / HPC "CASSIOPEIA" from "an improvised (pasture) source
Actually it all started from the fact that I do not have a power supply for Kaskiv E11 ... When I have are dead, ordinary 30R. as AAA batteries I started looking for an alternative to them. For the pocket - the mobile variant of an alternative is not found, but for desktop-Ammunition - here it is: I took a voltage regulator 7805, pinned him three "Conder" hung "bridge" connected to the power supply from the modem - like working. The bridge took a big (KTS402) - 7805 to strengthen him more comfortable (one screw strung) and in general it is a supporting structure for the entire circuit. Possible between the bridge and the stabilizer clamp the metal plate for heat dissipation. You can take a low profile bridge, you can add Conder (before the bridge after the bridge), you can turn down ... For a complete happiness can put the fuse before the bridge and powerful diode (6-8 volts) after the regulator (to be extra protection). All of this farm was placed in Kaskinom cradle. If Kaskiv feed from a car battery or battery pack, there is no need to think where the plus power supply ... Sticks and go. Use the product 6 months - all OK. Slightly heated (normally) without a heatsink. Well that's all.Additionally, Oleg sent by the scheme and photograph the device:
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- Interface board cradle
- Input capacitor
- Stabilizer 7805
- Diode bridge KTS402
- Credle
- Output capacitor
- Sync cable
- Connector for power supply. Oleg used the "mom" to connect the modem power supply.
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