Pulled the old toaster apart. It's a simple bridge rectified supply with an output voltage of ~28Vpk. There's also a 12V supply for the heating relay, lever relay and timing and temperature controls that's running from a linear regulator, which can be dispensed with. Fortunately for me, the temperature control mechanism is rather crude - there's a thermistor that detects temperature and the heating relay is switched on and off depending on the resistance of the thermistor. I'll simply remove the control and timing electronics and replace them with a simple push-button switch.
160 ohm, 1/2 watt carbon film resistor (R-ohm brand works excellently) taped to the fuse or to the side of a plastic bag filled with flammable gas mixture. Run two long 18 ga. (long extension cord) wires back to a plug that can be momentarily inserted in a 120 volt household outlet. This ignitor makes a nice, mostly isotropic blow torch flame for about a second or two. You would too if YOU wre rated for 1/2 a watt and someone put 90 watts through you. 
If you want to get classy (recommended for safety) fuse the firing circuit for a couple of amps and use a 120-120 isolation xfmer.
These resistors are uniformly repeatable, very reliable ignitors and dirt cheap.
If you want to get classy (recommended for safety) fuse the firing circuit for a couple of amps and use a 120-120 isolation xfmer.
These resistors are uniformly repeatable, very reliable ignitors and dirt cheap.
I second the resistor ideas!
I was once sitting at my bench,being bored...frying resistors with a 12V SLA battery.. The 1/2W to 1W low-ohm resistors (4.7-10ohms) lit up nicely,a nice orange glow,and some smoke,until it went open-circuit. Some even flamed-up a bit.
I even had a couple of wire wounds glowing orange (the whole thing,cement and all!)
I thought "Hey,these might make good ignitors!"
The model rocket ignitors work well also..I've used those countless times. A 2L bottle full of oxy+acet makes a BIG boom!
I was once sitting at my bench,being bored...frying resistors with a 12V SLA battery.. The 1/2W to 1W low-ohm resistors (4.7-10ohms) lit up nicely,a nice orange glow,and some smoke,until it went open-circuit. Some even flamed-up a bit.
I even had a couple of wire wounds glowing orange (the whole thing,cement and all!)
I thought "Hey,these might make good ignitors!" The model rocket ignitors work well also..I've used those countless times. A 2L bottle full of oxy+acet makes a BIG boom!
rcavictim said:160 ohm, 1/2 watt carbon film resistor (R-ohm brand works excellently) taped to the fuse or to the side of a plastic bag filled with flammable gas mixture. Run two long 18 ga. (long extension cord) wires back to a plug that can be momentarily inserted in a 120 volt household outlet. This ignitor makes a nice, mostly isotropic blow torch flame for about a second or two. You would too if YOU wre rated for 1/2 a watt and someone put 90 watts through you.
Another cheap electronic component that could be used is a schottky diode. Forward bias them with enough voltage and they will go up in flames. 6 C cells in series works quite well as a power source! The smell is awful, however
Are you into RC electronics? If you have a spare radio, receiver, battery pack, and servo (with enough torque) you could use the servo to mechanically activate the trigger of a barbeque lighter.
DigitalJunkie said:I second the resistor ideas!
I was once sitting at my bench,being bored...frying resistors with a 12V SLA battery.. The 1/2W to 1W low-ohm resistors (4.7-10ohms) lit up nicely,a nice orange glow,and some smoke,until it went open-circuit. Some even flamed-up a bit.
I even had a couple of wire wounds glowing orange (the whole thing,cement and all!)
The model rocket ignitors work well also..I've used those countless times. A 2L bottle full of oxy+acet makes a BIG boom!
Exactly how I discovered the resistor trick - boredom and a batch of 10 ohm resistors. Applying the output of a 25.2V/2A trafo directly to small electrolytic caps is equally entertaining while the supply of parts lasts. And it smells awful. For a really good smoke bomb overload the crud out of a 2-watt carbon-comp. When the innards catches, it will smoke up a storm long after power is removed.
We used to light up 2-liter bottles of hydrogen back then too. And guess how we made the H2 (and who paid for the electricity)
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