Sunday, September 15, 2013

How I constructed a simple transistor switch

The output pads from the Deltang receiver/controllers (Rx60-22 and Rx61-22) are restricted to 3 volts and can only handle the load of one LED. To enable each pad to switch higher voltage/current devices a simple transistor switch is needed. The wiring circuit for this switch is provided on the Deltang website and the three components required cost less than £2.00 in total.

I bought the electronic items needed for each switch from
  • a IRF3706 N-Channel Mosfet transistor
  • a 100 ohm resistor
  • a 10k ohm transistor
The two resistors (100R and 10k) were soldered together and a wire attached to the other end of the 10k resistor.

A (yellow) wire was soldered to the middle leg of the MOSFET and the resistors attached to the other two legs (with the 100R resistor leading to the left leg).

A piece of heatshrink sleeving was slipped over the middle lead ........

...... and a (purple wire soldered to the 100R resistor and another piece of heatshrink slipped over them.

After testing, the whole assembly was wrapped in heatshrink as the mounting bracket of the MOSFET is live and so needs insulating.

The purple wire was soldered to the lead from pad on the receiver/controller, the black wire was soldered to the negative lead from the battery and the yellow lead connected to the device needing to be remotely switched (eg a cluster of LEDs, the supply to a sound card, the whistle input on a sound card, etc.)

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